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JEE Main 2019 — Physical Chemistry

Chemistry Physical Chemistry questions from JEE Main 2019.

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127 Physical Chemistry Questions from 2019

Enthalpy of sublimation of iodine is $24 cal {g}^{-1}$ at $200^{\circ}C$ . If specific heat of ${I}_{2}$ (s) and ${I}_{2}$ (vap) are $0.055$ and $0.031 cal {g}^{-1}{K}^{-1}$ respectively, then enthalpy of sublimation of iodine at $250^{\circ}C$ in $cal {g}^{-1}$ is:

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If $p$ is the momentum of the fastest electron ejected from a metal surface after the irradiation of light having wavelength $\lambda ,$ then for $1.5 p$ momentum of the photoelectron, the wavelength of the light should be: (Assume kinetic energy of ejected photoelectron to be very high in comparison to work function)

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Which one of the following about an electron occupying the 1s orbital in a hydrogen atom is incorrect? (The Bohr radius is represented by ${a}_{0}$ ).

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The $pH$ of a $0.02 M$ $N{H}_{4}Cl$ solution will be [Given: ${K}_{b}(N{H}_{4}OH)={10}^{-5}$ and $\mathrm{log}⁡2=0.301$]

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For emission line of atomic hydrogen from ${n}_{i}=8$ to ${n}_{f}=n,$ the plot of wave number $(\overset{-}{v})$ against $(\frac{1}{{n}^{2}})$ will be: (The Rydberg constant, ${R}_{H}$ is in wave number unit)

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The standard reaction Gibbs energy for a chemical reaction at an absolute temperature $\mathrm{T}$ is given by $\Delta \mathrm{G}^{\circ}=\mathrm{A}-\mathrm{BT}$ where A and $B$ are non-zero constants. Which of the following is true about this reaction?

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$\mathrm{K}_{2} \mathrm{HgI}_{4}$ is $40 \%$ ionised in aqueous solution. The value of its van't Hoff factor (i) is:

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In order to oxidize a mixture of one mole of each of $Fe{C}_{2}{O}_{4},F{e}_{2}{({C}_{2}{O}_{4})}_{3},FeS{O}_{4}$ and $F{e}_{2}{(S{O}_{4})}_{3}$ in acidic medium, the number of moles of $KMn{O}_{4}$ is:

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The mole fraction of a solvent in aqueous solution of a solute is $0.8.$ The molality (in mol ${kg}^{-1}$ ) of the aqueous solution is:

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$25 g$ of an unknown hydrocarbon upon burnig produces $88 g$ of $C{O}_{2}$ and $9g$ of ${H}_{2}O.$ This unknown hydrocarbon contains:

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Among the following, the energy of $2s$ orbital is lowest in:

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For silver, ${C}_{p}(J{K}^{-1}mo{l}^{-1})=23+0.01T.$ If the temperature $(T)$ of $3$ moles of silver is raised from $300 K to 1000 K at 1 atm$ pressure, the value of $\Delta H$ will be close to:

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Which one of the following graphs between molar conductivity $({\Lambda }_{m})$ versus $\sqrt{C}$ is correct?

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$50 \mathrm{mL}$ of $0.5 M$ oxalic acid is needed to neutralize $25 \mathrm{mL}$ of sodium hydroxide solution. What is the amount of $\mathrm{NaOH}$ in $50 \mathrm{mL}$ of the given sodium hydroxide solution?

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A solution of $Ni{(N{O}_{3})}_{2}$ is electrolyzed between platinum electrode $0.1$ Faraday electricity. How many mole of $Ni$ will be deposited at the cathode?

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At $300 K$ and $1$ atmospheric pressure, $10 mL$ of a hydrocarbon required $55 mL$ of ${O}_{2}$ for complete combustion, and $40 mL$ of $C{O}_{2}$ is formed. The formula of the hydrocarbon is:

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For a reaction, ${N}_{2}(g)+3{H}_{2}(g)\longrightarrow 2N{H}_{3}(g)$, identify di-hydrogen $({H}_{2})$ as a limiting reagent in the following reaction mixtures.

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For the following reaction, the mass of water produced from $445 g$ of ${C}_{57}{H}_{110}{O}_{6}$ is: $2 {C}_{57}{H}_{110}{O}_{6}(s)+163{O}_{2}(g)\rightarrow 114 {\mathrm{CO}}_{2}(g)+110{H}_{2}O(l)$

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The decreasing order of electrical conductivity of the following aqueous solutions is: $(A)$ $0.1 M$ Formic acid, $(B)$ $0.1 M$ Acetic acid, $(C)$ $0.1 M$ Benzoic acid.

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In the following reaction; $xA\rightarrow yB$ ${\mathrm{log}}_{10}⁡[-\frac{d[A]}{dt}]={\mathrm{log}}_{10}⁡[-\frac{d[B]}{dt}]+0.3010$ ‘A’ and ‘B’ respectively can be:

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For the cell $\mathrm{Zn}(\mathrm{s})\left|\mathrm{Zn}^{2+}(\mathrm{aq}) \| \mathrm{M}^{\mathrm{x}+}(\mathrm{aq})\right| \mathrm{M}(\mathrm{s}),$ different half cells and their standard electrode potentials are given below: ![JEE Main 2019 Chemistry, Electrochemistry — question figure](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Electrochemistry/648b5a67417cc3fb48d66769/question_1__q_648b5a67417cc3fb48d66769__cdn-question-pool.getmarks.app__8_ywllHaThmbgd-amuF-6N-zUeHl1_cT31EEiZ4jxW4.original.fullsiz__b719905bd0_final_ppt_sync.png) If $\mathrm{E}_{\mathrm{Zn}^{2+} / \mathrm{Zn}}^{\circ}=-0.76 \mathrm{~V},$ which cathode will give a maximum value of $E_{\text {cell }}^{0}$ per electron transferred?

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$5$ moles of $A{B}_{2}$ weigh $125\times {10}^{-3} kg$ and $10$ moles of ${A}_{2}{B}_{2}$ weigh $300\times {10}^{-3} kg$ . The molar mass of A $({M}_{A})$ in $kg {mol}^{-1}$ are:

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An ideal gas undergoes isothermal compression from $5 {m}^{3}$ to $1 {m}^{3}$ against a constant external pressure of $4 N{m}^{-2}$. The heat released in this process is $24 J {\mathrm{mol}}^{-1}{K}^{-1}$ and is used to increase the pressure of $1$ mole of $\mathrm{Al}$. The temperature of $\mathrm{Al}$ increases by:

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Molal depression constant for a solvent is $4.0 K kg mo{l}^{-1}.$ The depression in the freezing point of the solvent for $0.03 mol k{g}^{-1}$ solution of ${K}_{2}S{O}_{4}$ is: (Assume complete dissociation of the electrolyte)

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Which of the following combination of statements is true regarding the interpretation of the atomic orbitals? $(A)$ An electron in an orbital of high angular momentum stays away from the nucleus than an electron in the orbital of lower angular momentum. $(B)$ For a given value of the principal quantum number, the size of the orbit is inversely proportional to the azimuthal quantum number. $(C)$ According to wave mechanics, the ground state angular momentum is equal to $\frac{h}{2\pi }$ . $(D)$ The plot of $\psi$ Vs $r$ for various azimuthal quantum numbers, shows peak shifting towards higher $r$ value.

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$5$ moles of an ideal gas at $100 K$ are allowed to undergo reversible compression till its temperature becomes $200 K.$ If ${C}_{V}=28 J {K}^{-1},$ calculate $\Delta U$ and $\Delta pV$ for the process. $(R=8.0 J {K}^{-1} mo{l}^{-1})$

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In the reaction of oxalate with permanganate in acidic medium, the number of electrons involved in producing one molecule of ${\mathrm{CO}}_{2}$ is:

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Consider the given plots for a reaction obeying Arrhenius equation $(0^{\circ}C<T<300^{\circ}C):$ ($K$and ${E}_{a}$ are rate constant and activetion energy, respectively ) (I) ![JEE Main 2019 Chemistry, Chemical Kinetics — question figure 1](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Chemical_Kinetics/648b5a67417cc3fb48d666c7/question_1__q_648b5a67417cc3fb48d666c7__cdn-question-pool.getmarks.app__b67bb79e-7840-4e51-91c8-73f575d0d4e4-image__ba5ff69c82_final_ppt_sync.png) (II) ![JEE Main 2019 Chemistry, Chemical Kinetics — question figure 2](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Chemical_Kinetics/648b5a67417cc3fb48d666c7/question_2__q_648b5a67417cc3fb48d666c7__cdn-question-pool.getmarks.app__0c91ad90-7d94-434c-900b-ac4eb1f7183c-image__af156df8e7_final_ppt_sync.png)

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$1 g$ of a non-volatile non-electrolyte solute is dissolved in $100 g$ of two different solvents $A$ and B whose ebullioscopic constants are in the ratio of $1:5$. The ratio of the elevation in their boiling points, $\frac{\Delta {T}_{b}(A)}{\Delta {T}_{b}(B)}$, is: (assuming they have the same molar mass)

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If the standard electrode potential for a cell is $2 V$ at $300 K,$ the equilibrium constant $(K)$ for the reaction. $Zn(s)+C{u}^{2+}(aq)\rightleftharpoons Z{n}^{2+}(aq)+Cu(s)$ at $300 K$ is approximately: $(R=8 J{K}^{-1}mo{l}^{-1}, F=96000 C mo{l}^{-1})$

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Heat treatment of muscular pain involves radiation of wavelength of about $900 \mathrm{nm}$. Which spectral line of $\mathrm{H}$ atom is suitable for this purpose? $\left[\mathrm{R}_{\mathrm{H}}=1 \times 10^{5} \mathrm{~cm}^{-1} \cdot \mathrm{h}=6.6 \times 10^{-34} \mathrm{Js}, \mathrm{c}=3 \times 10^{8} \mathrm{~ms}^{-1}\right]$

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The combination of plots which does not represent isothermal expansion of an ideal gas is $(A)$ ![JEE Main 2019 Chemistry, Thermodynamics (C) — question figure 1](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Thermodynamics_C/648b5a67417cc3fb48d6693a/question_1__q_648b5a67417cc3fb48d6693a__cdn-question-pool.getmarks.app__1102d293-2946-4257-98ce-e970539b2883-image__cf8810d9e7_final_ppt_sync.png) $(B)$ ![JEE Main 2019 Chemistry, Thermodynamics (C) — question figure 2](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Thermodynamics_C/648b5a67417cc3fb48d6693a/question_2__q_648b5a67417cc3fb48d6693a__cdn-question-pool.getmarks.app__5ae9c384-6cb9-4ea3-b1c2-32d55c7eda55-image__fa4971a274_final_ppt_sync.png) $(C)$ ![JEE Main 2019 Chemistry, Thermodynamics (C) — question figure 3](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Thermodynamics_C/648b5a67417cc3fb48d6693a/question_3__q_648b5a67417cc3fb48d6693a__cdn-question-pool.getmarks.app__e39874e8-3e73-4fa0-a9cf-58d7a11f6774-image__757bcf7d48_final_ppt_sync.png) $(D)$ ![JEE Main 2019 Chemistry, Thermodynamics (C) — question figure 4](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Thermodynamics_C/648b5a67417cc3fb48d6693a/question_4__q_648b5a67417cc3fb48d6693a__cdn-question-pool.getmarks.app__3b813919-9505-47be-8a4d-13f37c9529c3-image__75170c7e7b_final_ppt_sync.png)

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The amount of sugar $({C}_{12}{H}_{22}{O}_{11})$ required to prepare $2L$ of its $0.1 M$ aqueous solution is:

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Consider the following reduction processes: ${\mathrm{Zn}}^{2+}+2{e}^{-}\rightarrow \mathrm{Zn}(s);{E}^{o}=-0.76 V$ ${\mathrm{Ca}}^{2+}+2{e}^{-}\rightarrow \mathrm{Ca}(s);{E}^{o}=-2.87 V$ ${\mathrm{Mg}}^{2+}+2{e}^{-}\rightarrow \mathrm{Mg}(s);{E}^{o}=-2.36 V$ ${\mathrm{Ni}}^{2+}+2{e}^{-}\rightarrow \mathrm{Ni}(s);{E}^{o}=-0.25 V$ The reducing power of the metals increases in the order:

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The percentage composition of carbon by mole in methane is:

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The ground state energy of a hydrogen atom is $-13.6 \mathrm{eV}$. The energy of second excited state of ${\mathrm{He}}^{+}$ ion in $\mathrm{eV}$ is:

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Consider the following reversible chemical reactions: ${A}_{2}(g)+{B}_{2}(g)\overset{{k}_{1}}{\rightleftharpoons }2AB(g)$ .....(1) $6AB(g)\overset{{k}_{2}}{\rightleftharpoons }3{A}_{2}(g)+3{B}_{2}(g)$ .....(2) The relation between ${K}_{1}$ and ${K}_{2}$ is:

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For the following reaction, equilibrium constant are given: $S(s)+{O}_{2}(g)\rightleftharpoons S{O}_{2}(g);{K}_{1}={10}^{52}$ $2S(s)+3{O}_{2}(g)\rightleftharpoons 2S{O}_{3}(g);{K}_{2}={10}^{129}$ The equilibrium constant for the reaction, $2{SO}_{2}(g)+{O}_{2}(g)\rightleftharpoons 2S{O}_{3}(g)$ is:

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Which one of the following equations does not correctly represent the first law of thermodynamics for the given processes involving an ideal gas? (Assume non- expansion work is zero)

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$5.1 g {\mathrm{NH}}_{4}\mathrm{SH}$ is introduced in $3.0 L$ evacuated flask at ${327}^{o}C$ . $30%$ of the solid ${\mathrm{NH}}_{4}\mathrm{SH}$ is decomposed to ${\mathrm{NH}}_{3}$ and ${H}_{2}S$ as gases. The ${K}_{P}$ of the reaction at ${327}^{o}C$ is $(R=0.082 L \mathrm{atm} {\mathrm{mol}}^{-1}{K}^{-1},\mathrm{Molar} \mathrm{mass} \mathrm{of} S=32 g {\mathrm{mol}}^{-1}, \mathrm{Molar} \mathrm{mass} \mathrm{of} N=14g {\mathrm{mol}}^{-1})$

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What are the values of $\frac{{K}_{p}}{{K}_{c}}$ for the following reactions at $300 K$ respectively? (At $300 K, \mathrm{RT}=24.62 {\mathrm{dm}}^{2}\mathrm{atm} {\mathrm{mol}}^{-1}$ ) ${N}_{2}(g)+{O}_{2}(g)\rightleftharpoons 2\mathrm{NO}(g)$ ${N}_{2}{O}_{4}(g)\rightleftharpoons 2\mathrm{NO}(g)$ ${N}_{2}(g)+3{H}_{2}(g)\rightleftharpoons 2{\mathrm{NH}}_{3}(g)$

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For the reaction $2A+B\rightarrow C$ , the values of initial rate at different reactant concentrations are given in the table below. The rate law for the reactions is:<table class="pyq-table"><tbody><tr><th>$[A](mol{L}^{-1})$</th><th>$[B](mol{L}^{-1})$</th><th>$Initial Rate$ $(mol{L}^{-1}{s}^{-1})$</th></tr><tr><td>0.05</td><td>0.05</td><td>0.045</td></tr><tr><td>0.10</td><td>0.05</td><td>0.090</td></tr><tr><td>0.20</td><td>0.10</td><td>0.72</td></tr></tbody></table>

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The reaction $2 \mathrm{X} \rightarrow \mathrm{B}$ is a zeroth order reaction. If the initial concentration of $\mathrm{X}$ is $0.2 \mathrm{M}$, the half-life is $6 \mathrm{~h}$. When the initial concentration of $X$ is $0.5 \mathrm{M}$, the time required to reach its final concentration of $0.2 \mathrm{M}$ will be

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The following results were obtained during kinetic studies of the reaction. $2A+B\rightarrow$ product <table class="pyq-table"><tbody><tr><td>Experiment</td><td>$[A]$ $(\mathrm{in} \mathrm{mol} {L}^{-1})$</td><td>$[B]$ $(in mol {L}^{-1})$</td><td>Initial rate of reaction $(\mathrm{in} \mathrm{mol} {L}^{-1} \mathrm{min}{ }^{-1})$</td></tr><tr><td>$I$</td><td>$0.10$</td><td>$0.20$</td><td>$6.93\times {10}^{-3}$</td></tr><tr><td>$\mathrm{II}$</td><td>$0.10$</td><td>$0.25$</td><td>$6.93\times {10}^{-3}$</td></tr><tr><td>$\mathrm{III}$</td><td>$0.20$</td><td>$0.30$</td><td>$1.386\times {10}^{-2}$</td></tr></tbody></table> The time (in minutes) required to consume half of $\text{A}$ is

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The reaction $\mathrm{MgO}(\mathrm{s})+\mathrm{C}(\mathrm{s}) \rightarrow \mathrm{Mg}(\mathrm{s})+\mathrm{CO}(\mathrm{g}),$ for which $\Delta \mathrm{H}^{\circ}=+491.1 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $\Delta \mathrm{S}^{\circ}=198.0 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}$ is not feasible at $298 \mathrm{~K}$. Temperature above which reaction will be feasible is

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For a reaction, consider the plot of $ln k$ versus $1/T$ given in the figure. If the rate constant of this reaction at $400 K$ is ${10}^{-5}{s}^{-1}$ , then the rate constant at $500 K$ is: ![JEE Main 2019 Chemistry, Chemical Kinetics — question figure](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Chemical_Kinetics/648b5a67417cc3fb48d6693f/question_1__q_648b5a67417cc3fb48d6693f__cdn-question-pool.getmarks.app__e6b68920-f87c-4f00-a066-daa436691c8c-image__9ba41c9608_final_ppt_sync.png)

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If a reaction follows the Arrhenius equation, the plot $\ln k$ vs $\frac{1}{(\mathrm{RT})}$ gives straight line with a gradient $(-\mathrm{y})$ unit. The energy required to activate the reactant is:

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The elevation in boiling point for $1$ molal solution of glucose is $2 K$. The depression in freezing point for $2$ molal solution of glucose in the same solvent is $2 K.$ The relation between ${K}_{b}$ and ${K}_{f}$ is:

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$8 g$ of $\mathrm{NaOH}$ is dissolved in $18g$ of ${H}_{2}O$. Mole fraction of $\mathrm{NaOH}$ in solution and molality (in $\mathrm{mol} {\mathrm{kg}}^{-1}$) of the solution respectively are:

medium
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The entropy change associated with the conversion of $1 kg$ of ice at $273 K$ to water vapours at $383 K$ is: (Specific heat of water liquid and water vapour are $4.2 kJ {K}^{-}$ and $2.0 kJ {K}^{-1}k{g}^{-1}$ ; heat of liquid fusion and vaporization of water are $334 kJ k{g}^{-1}$ and $2491 kJ k{g}^{-1}$ , respectively). ( $log$ $273=2.436,\mathrm{log}⁡373=2.572,\mathrm{log}⁡383=2.583$ )

medium
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A process has $\Delta H=200 J mo{l}^{-1}$ and $\Delta S=40 J{K}^{-1}mo{l}^{-1}.$ Out of the values given below choose the minimum temperature above which the process will be spontaneous:

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In which one of the following equilibria, ${K}_{p}\neq {K}_{c}?$

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The incorrect match in the following is:

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The isoelectronic set of ions is:

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If the de Broglie wavelength of the electron in ${n}^{th}$ Bohr orbit in a hydrogenic atom is equal to $1.5 \pi {a}_{0}$ $({a}_{0}$ is Bohr radius$)$, then the value of $\frac{n}{z}$ is:

medium
mcq

Consider the following statements $(a)$ The pH of a mixture containing $400 mL$ of $0.1 M {H}_{2}S{O}_{4}$ and $400 mL$ of $0.1 M NaOH$ will be approximately $1.3.$ $(b)$ Ionic product of water is temperature dependent. $(c)$ A monobasic acid with ${K}_{a}={10}^{-5}$ has a $pH=5$ . The degree of dissociation of this acid is $50%$ . $(d)$ The Le Chatelier's principle is not applicable to common-ion effect. The correct statements are:

hard
mcq

What is the work function of the metal if the light of wavelength $4000\overset{o}{A}$ generates photoelectrons of velocity $6\times {10}^{5} {\mathrm{ms}}^{-1}$ from it? (Mass of electron $=9\times {10}^{-31}\mathrm{kg}$, velocity of light $=3\times {10}^{8}{\mathrm{ms}}^{-1}$, Planck's constant $=6.626\times {10}^{-34}\mathrm{Js}$, Charge of electron $=6.626\times {10}^{-34}\mathrm{Js}$)

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For any given series of spectral lines of atomic hydrogen, let $\Delta \overset{-}{v}={\overset{-}{v}}_{max}-{\overset{-}{v}}_{min}$ be the difference in maximum and minimum wave number in $c{m}^{-1}$. The ratio $\Delta {\overset{-}{v}}_{Lyman}/\Delta {\overset{-}{v}}_{Balmar}$ is

hard
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For the reaction of ${H}_{2}$ with ${I}_{2}$, the rate constant is $2.5\times {10}^{-4} d{m}^{3}mo{l}^{-1}{s}^{-1}$ at ${327}^{o}C$ and $1.0 d{m}^{3} mol-1{s}^{-1}$ at $527^{\circ}C$ . The activation energy for the reaction, in $kJ mol-1$ is: $(R=8.314 J{K}^{-1}mo{l}^{-1})$

hard
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If ${K}_{\mathrm{sp}}$ of ${\mathrm{Ag}}_{2}{\mathrm{CO}}_{3}$ is $8\times {10}^{-12}$ , the molar solubility of ${\mathrm{Ag}}_{2}{\mathrm{CO}}_{3}$ in $0.1 M {\mathrm{AgNO}}_{3}$ is:

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In an acid-base titration, $0.1 M HCl$ solution was added to the $NaOH$ solution of unknown strength. Which of the following correctly shown the change of $pH$ of the titration mixture in this experiment? ![JEE Main 2019 Chemistry, Ionic Equilibrium — question figure](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Ionic_Equilibrium/648b5a66417cc3fb48d66500/question_1__q_648b5a66417cc3fb48d66500__cdn-question-pool.getmarks.app__7a5313b8-4efb-4a9a-b8fa-e7d0bdfdfbbb-image__050446493c_final_ppt_sync.png)

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In a chemical reaction, $A+2B\overset{K}{\rightleftharpoons }2C+D$ , the initial concentration of $B$ was $1.5$ times of the concentration of $A$ , but the equilibrium concentrations of $A$ and $B$ were found to be equal. The equilibrium constant $(K)$ for the chemical reaction is:

medium
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The standard Gibbs energy for the given cell reaction in $kJ mo{l}^{-1}$ at $298 K$ is: $Zn(s)+C{u}^{2+}(aq)\longrightarrow Z{n}^{2+}(aq)+Cu(s)$ , ${E}^{0}=2 V at 298 K$ $(Faraday's constant ,F=96000 C mo{l}^{-1})$

medium
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Given the equilibrium constant: $\mathrm{K}_{\mathrm{C}}$ of the reaction: $\mathrm{Cu}(\mathrm{s})+2 \mathrm{Ag}^{+}(\mathrm{aq}) \rightarrow \mathrm{Cu}^{2+}(\mathrm{aq})+2 \mathrm{Ag}(\mathrm{s})$ is $10 \times 10^{15}$ calculate the $E_{\text {cell }}^{0}$ of this reaction at $298 \mathrm{~K}$ $\left[2.303 \frac{\mathrm{RT}}{\mathrm{F}}\right.$ at $\left.298 \mathrm{~K}=0.059 \mathrm{~V}\right]$

hard
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${\wedge }_{m}^{o}$ for $\mathrm{NaCl}, \mathrm{HCl}$ and $\mathrm{NaA}$ are $126.4, 425.9$ and $100.5 S {\mathrm{cm}}^{2}{\mathrm{mol}}^{-1}$ respectively. If the conductivity of $0.001 M \mathrm{HA}$ is $5\times {10}^{-5}S {\mathrm{cm}}^{-1}$, degree of dissociation of $\mathrm{HA}$ is

hard
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A solution is prepared by dissolving 0.6 g of urea (molar mass $=60 g mo{l}^{-1}$) and $1.8 g$ of glucose (molar mass $=180 g mo{l}^{-1}$) in 100 mL of water at ${27}^{o}C.$ The osmotic pressure of the solution is: ($R=0.08206 L$$\text{ atm}$ ${K}^{-1} mo{l}^{-1}$)

medium
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What would be the molality of 20% (mass/mass) aqueous solution of $KI$ ? (molar mass of $KI=166 g mo{l}^{-1}$ )

medium
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$0.27 g$ of a long chain fatty acid was dissolved in $100{ cm}^{3}$ of hexane. $10 mL$ of this solution was added dropwise to the surface of water in a round watch glass. Hexane evaporates and a monolayer is formed. The distance from edge to centre of the watch glass is $10 cm$ . What is the height of the monolayer? [Density of fatty acid $=0.9 g c{m}^{-3};\pi =3]$

hard
mcq

For the solution of the gases $w,x,y$ and $z$ in water at $298 K,$ the Henry's law constants $({K}_{H})$ are $0.5,2,35$ and $40 kbar,$ respectively. The correct plot for the given data is:

hard
mcq

For the reaction, $2S{O}_{2}(g)+{O}_{2}(g)\rightleftharpoons 2S{O}_{3}(g),$ $\Delta H=-57.2 kJ mo{l}^{-1} and {K}_{c}=1.7\times {10}^{16}.$ Which of the following statements is incorrect?

hard
mcq

The ${71}^{\mathrm{st}}$ electron of an element $X$ with an atomic number of $71$ enters the orbital:

medium
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Consider the given plot of enthalpy of the following reaction between $A$ and $B.$ $A+B\rightarrow C+D.$ Identify the incorrect statement. ![JEE Main 2019 Chemistry, Chemical Kinetics — question figure](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Chemical_Kinetics/648b5a66417cc3fb48d66505/question_1__q_648b5a66417cc3fb48d66505__cdn-question-pool.getmarks.app__0cf951f8-f7fa-4899-a467-a7d410bfe384-image45__82f0914e33_final_ppt_sync.png)

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Two solids dissociate as follows: $A(s)\rightleftharpoons B(g)+C(g); {K}_{{P}_{1}}=x {\mathrm{atm}}^{2}$ $D(s)\rightleftharpoons C(g)+E(g); {K}_{{P}_{2}}=y {\mathrm{atm}}^{2}$ The total pressure when both the solids dissociate simultaneously is:

medium
mcq

$20 \mathrm{ml}$ of ${\text{0.1 M H}}_{2}{\mathrm{SO}}_{4}$ solution is added to $30 \mathrm{mL}$ of $0.2 M {\mathrm{NH}}_{4}\mathrm{OH}$ solution. The $\mathrm{pH}$ of the resultant mixture is: $[{\mathrm{pk}}_{b} \mathrm{of} {\mathrm{NH}}_{4}\mathrm{OH}=4.7]$

hard
mcq

In the cell, $\mathrm{Pt}(s)|{H}_{2}(g, 1\mathrm{bar})| \mathrm{HCl} (\mathrm{aq})|\mathrm{AgCl}(s)|\mathrm{Ag}(s)|\mathrm{Pt}(s),$the cell potential is $0.92 V$ when a ${10}^{-6}$ molar $\mathrm{HCl}$ solution is used. The standard electrode potential of $\mathrm{Ag}|\mathrm{AgCl}|{\mathrm{Cl}}^{-}$ electrode is: (Given, $\frac{2.303\mathrm{RT}}{F}=0.06 V$ at $298 K$)

hard
mcq

For a diatomic ideal gas in a closed system, which of the following plots does not correctly describe the relation between various thermodynamic quantities?

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Consider the reversible isothermal expansion of an ideal gas in a closed system at two different temperatures ${T}_{1}$ and ${T}_{2}({T}_{1}<{T}_{2})$ . The correct graphical depiction of the dependence of work done $(w)$ vs the final volume $(V)$ is:

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For the chemical reaction $\mathrm{X} \rightleftharpoons \mathrm{Y},$ the standard reaction Gibbs energy depends on temperature $T$ (in $K$ ) as $\Delta_{\mathrm{r}} \mathrm{G}^{\circ}\left(\right.$ in $\left.\mathrm{kJ} \mathrm{mol}^{-1}\right)=120-\frac{3}{8} \mathrm{~T}$ The major component of the reaction mixture at $\mathrm{T}$ is :

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The freezing point of a diluted milk sample is found to be $-0.2^{\circ} \mathrm{C},$ while it should have been $-0.5^{\circ} \mathrm{C}$ for pure milk. How much water has been added to pure milk to make the diluted sample?

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A solution of sodium sulphate contains $92 g$ of ${\mathrm{Na}}^{+}$ ions per kilogram of water. The molality of ${\mathrm{Na}}^{+}$ ions in that solution in $\mathrm{mol} {\mathrm{kg}}^{-1}$ is:

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Molecules of benzoic acid $({C}_{6}{H}_{5}\mathrm{COOH})$ dimerise in $30 g$ of benzene. ' $w$ ' $g$ of benzoic acid shows a depression in freezing point equal to $2 K$. If the percentage association of the acid to form dimer in the solution is $80$, then $w$ is: $($ Given that ${K}_{f}=5{\mathrm{Kmol}}^{-1}$, molar mass of benzoic acid $=122 {\mathrm{gmol}}^{-1})$

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The electrons are more likely to be found: ![JEE Main 2019 Chemistry, Structure of Atom — question figure](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Structure_of_Atom/648b5a67417cc3fb48d66832/question_1__q_648b5a67417cc3fb48d66832__cdn-question-pool.getmarks.app__7f1df81b-88d7-499f-a053-737f39b0fc71-image__46c10ac7e3_final_ppt_sync.png)

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The anodic half-cell of lead-acid battery is recharged using electricity of $0.05$ Faraday. The amount of ${\mathrm{PbSO}}_{4}$ electrolyzed in $g$ during the process is: (Molar mass of ${\mathrm{PbSO}}_{4}=303g {\mathrm{mol}}^{-1}$)

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Which one of the following statements regarding Henry's law is not correct?

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The ratio of the shortest wavelength of two spectral series of hydrogen spectrum is found to be about $9$. The spectral series are:

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The freezing point of a $4%$ aqueous solution of $X$ is equal to the freezing point of a $12%$ aqueous solution of $Y$. If the molecular weight of $X$ is $A$, then the molecular weight of $Y$ will be

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$N{O}_{2}$ required for a reaction is produced by the decomposition of ${N}_{2}{O}_{5}$ in $CC{l}_{4}$ as per the equation, $2{N}_{2}{O}_{5}(g)\rightarrow 4N{O}_{2}(g)+{O}_{2}(g).$ The initial concentration of ${N}_{2}{O}_{5}$ is $3.00 mol {L}^{-1}$ and it is $2.75 mol {L}^{-1}$ after 30 minutes. The rate of formation of $N{O}_{2}$ is:

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The given plots represent the variation of the concentration of a reactant $R$ with time for two different reactions $(i)\mathrm{and}(\mathrm{ii})$. The respective orders of the reaction are (i) ![JEE Main 2019 Chemistry, Chemical Kinetics — question figure 1](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Chemical_Kinetics/648b5a66417cc3fb48d6649c/question_1__q_648b5a66417cc3fb48d6649c__cdn-question-pool.getmarks.app__05cce7aa-b495-498b-b6a5-299428a6090e-image__6a0a697309_final_ppt_sync.png) (ii) ![JEE Main 2019 Chemistry, Chemical Kinetics — question figure 2](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Chemical_Kinetics/648b5a66417cc3fb48d6649c/question_2__q_648b5a66417cc3fb48d6649c__cdn-question-pool.getmarks.app__fe017694-9417-483d-9851-73f53fa05d16-image__7ca6779a11_final_ppt_sync.png)

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Consider the reaction $\mathrm{N}_{2}(\mathrm{~g})+3 \mathrm{H}_{2}(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NH}_{3}(\mathrm{~g})$ The equilibrium constant of the above reaction is $\mathrm{K}_{\mathrm{P}}$. If pure ammonia is left to dissociate, the partial pressure of ammonia at equilibrium is given by (Assume that $\mathrm{P}_{\mathrm{NH}_{3}}< < \mathrm{P}_{\text {total }}$ at equilibrium)

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An example of a disproportionation reaction is

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Calculate the standard cell potential (in V) of the cell in which the following reaction takes place: ${Fe}^{2+} (aq)+A{g}^{+}(aq)\rightarrow F{e}^{3+}(aq)+Ag(s)$ Given that ${E}_{{\mathrm{Ag}}^{+}/Ag}^{o}=x V$ ${E}_{{Fe}^{2+}/Fe}^{o}=y V$ ${E}_{{Fe}^{3+}/Fe}^{o}=z V$

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For a reaction scheme $A\overset{{ k}_{1} }{\rightarrow }B\overset{{ k}_{2} }{\rightarrow }C,$ if the net rate of formation of B is set to be zero then the concentration of B is given by:

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What is the molar solubility of $AI{(OH)}_{3}$ in $0.2$ $M NaOH$ solution? Given that, solubility product of $\mathrm{Al}{(OH)}_{3}=2.4\times {10}^{-24}$ :

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The standard electrode potential ${E}^{o}$ and its temperature coefficient $(\frac{\mathrm{dE}}{\mathrm{dT}})$ for a cell are $2V$ and $-5{\times 10}^{-4} V{K}^{-1}$ at $300 K$, respectively. The reaction is $\mathrm{Zn}(s)+{\mathrm{Cu}}^{2+}(\mathrm{aq})\rightarrow {\mathrm{Zn}}^{2+}(\mathrm{aq})+\mathrm{Cu}(s)$. The standard reaction enthalpy $({\Delta }_{r}{H}^{-})$ at $300K$ in $mo{l}^{-1}$ is $[$Use $R=8J{K}^{-1}{\mathrm{mol}}^{-1}$ and $F=96,500C{\mathrm{mol}}^{-1}]$

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At room temperature, a dilute solution of urea is prepared by dissolving $0.60 g$ of urea in $360 g$ of water. If the vapour pressure of pure water at this temperature is $35 mm Hg$ , lowering of vapour pressure will be: (molar mass of urea $=60 g mo{l}^{-1}$ )

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A mixture of $100 m\mathrm{mol}$ of $\mathrm{Ca}{(\mathrm{OH})}_{2}$ and $2g$ of sodium sulphate was dissolved in water and the volume was made up to $100 \mathrm{mL}.$ What is the mass of calcium sulphate formed and the concentration of ${\mathrm{OH}}^{-}$ in resulting solution, respectively? (Molar mass of $\mathrm{Ca}{(\mathrm{OH})}_{2}, {\mathrm{Na}}_{2}{\mathrm{SO}}_{4}$ and ${\mathrm{CaSO}}_{4}$ are $74, 143$ and $136g {\mathrm{mol}}^{-1},$ respectively; ${K}_{\mathrm{sp}}$ of $\mathrm{Ca}{(\mathrm{OH})}_{2}\mathrm{is} 5.5\times {10}^{-6}$)

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Liquids $A$ and $B$ form an ideal solution in the entire composition range. At $350K,$ the vapour pressure of pure A and pure B are $7\times {10}^{3}\mathrm{Pa}$ and $12\times {10}^{3}\mathrm{Pa}$ , respectively. The composition of the vapour in equilibrium with a solution containing 40 mole percent of A at this temperature is:

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The amphoteric hydroxide is:

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Among the following, the set of parameters that represents path functions, is: i) $q+w$ ii) $q$ iii) $w$ iv) $H-TS$

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The quantum number of four electrons are given below: $I. n=4, l=2, {m}_{l}=–2, {m}_{s}=–1/2$ $II. n=3, l=2, {m}_{l}=1, {m}_{s}=+1/2$ $III. n=4, l=1, {m}_{l}=0, {m}_{s}=+1/2$ $IV. n=3, l=1, {m}_{l}=1, {m}_{s}=–1/2$ The correct order of their increasing energies will be:

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A solution containing $62 g$ ethylene glycol in $250 g$ water is cooled to $-{10}^{o}C$ . If ${K}_{f}$ for water is $1.86 K \mathrm{kg} {\mathrm{mol}}^{-1}$ , the amount of water (in $g$ ) separated as ice is:

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Given: $(i)$ $\text{C}(\mathrm{graphite})+{O}_{2}(g)\rightarrow {\mathrm{CO}}_{2}(g);$ ${\Delta rH}^{\Theta }=x \mathrm{kJ} {\mathrm{mol}}^{-1}$ $(\mathrm{ii})$ $C(\mathrm{graphite})+\frac{1}{2}{O}_{2}(g)\rightarrow \mathrm{CO}(g);$ ${\Delta rH}^{\Theta }=y \mathrm{kJ} {\mathrm{mol}}^{-1}$ $(\mathrm{iii}) \mathrm{CO}(g)+\frac{1}{2}{O}_{2}(g)\rightarrow {\mathrm{CO}}_{2}(g);$ ${\Delta rH}^{\Theta }=z \mathrm{kJ} {\mathrm{mol}}^{-1}$ Based on the above thermochemical equations, find out which one of the following algebraic relationships is correct?

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$25 \mathrm{~mL}$ of the given $\mathrm{HCl}$ solution requires $30 \mathrm{~mL}$ of $0.1 \mathrm{M}$ sodium carbonate solution. What is the volume of this $\mathrm{HCl}$ solution required to titrate $30 \mathrm{~mL}$ of $0.2 \mathrm{M}$ aqueous $\mathrm{NaOH}$ solution?

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Which of the graphs shown below does not represent the relationship between incident light and the electron ejected from metal surface?

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Two blocks of the same metal having same mass and at temperature $\mathrm{T}_{1},$ and $\mathrm{T}_{2}$, respectively, are brought in contact with each other and allowed to attain thermal equilibrium at constant pressure. The change in entropy, $\Delta \mathrm{S}$, for this process is :

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Consider the statements $S1$ and $S2$ : $S1$ : Conductivity always increases with decreases in the concentration of electrolyte. $S2$ : Molar conductivity always increases with decreases in the concentration of electrolyte. The correct option among the following

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Liquid $M$ and liquid $N$ form an ideal solution. The vapour pressures of pure liquids $M$ and $N$ are $450$ and $700 mmHg,$ respectively, at the same temperature. Then correct statements is: ( ${x}_{M}=Mole fraction of {'M}^{'} in solution;$ ${x}_{N}=Mole fraction of {'N}^{'}in solution;$ ${y}_{M}=Mole fraction of {'M}^{'} in vapour phase;$ ${y}_{N}=Mole fraction of {'N}^{'} in vapour phase;$ )

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The graph between ${|\psi |}^{2}$ and $r$ (radical distance) is shown below. This represents: ![JEE Main 2019 Chemistry, Structure of Atom — question figure](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Chemistry/images/Structure_of_Atom/648b5a66417cc3fb48d66600/question_1__q_648b5a66417cc3fb48d66600__cdn-question-pool.getmarks.app__3566efd8-a2cd-4f09-9b4b-a17a518848c2-image__ecf392cb0f_final_ppt_sync.png)

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For an elementary chemical reaction, ${A}_{2}⇄_{{k}_{-1}}^{{k}_{1}}2A$ , the expression for $\frac{d[A]}{\mathrm{dt}}$ is:

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During compression of a spring the work done is $10 kJ$ and $2 kJ$ escaped to the surroundings as heat. The change in internal energy, $\Delta U(in kJ)$ is:

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The minimum amount of ${O}_{2}(g)$ consumed per gram of reactant is for the reaction: (Given atomic mass: $Fe=56, O=16, Mg=24, P=31, C=12,H=1$ )

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A bacterial infection in an internal wound grows as ${N}^{'}(t)={N}_{0}exp⁡(t)$ , where the time $t$ is in hours. A dose of antibiotic, taken orally, needs 1 hour to reach the wound. Once it reaches there, the bacterial population goes down as $\frac{dN}{dt}=-5{N}^{2}$ . What will be the plot of $\frac{{N}_{0}}{N}$ vs $t$ after $1$ hour?

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An ideal gas is allowed to expand from $1 L$ to $10 L$ against a constant external pressure of $1$ bar. The work done in $kJ$ is:

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The vapour pressures of pure liquids $A$ and $B$are $400$ and $600\mathrm{mm}\mathrm{Hg}$ respectively at $298 K.$On mixing the two liquids, the sum of their volumes is equal to the volume of the final mixture. The mole fraction of liquid $B$ is $0.5$ in the mixture. The vapour pressure of the final solution, the mole fractions of components $A$ and $B$ in the vapour phase, respectively are

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The process with negative entropy change is:

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The osmotic pressure of a dilute solution of an ionic compound $XY$ in water is four times that of a solution $0.01 M BaC{l}_{2}$ in water. Assuming complete dissociation of the given ionic compounds in water, the concentration of $XY$ ( $in mol {L}^{-1}$ ) in solution is

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Given that, ${E}_{{O}_{2}/{H}_{2}O}^{o}=+1.23V;$ ${E}_{{S}_{2}{O}_{8}^{2-}/{\mathrm{SO}}_{4}^{2-}}^{o}=2.05V$ ${E}_{{\mathrm{Br}}_{2}/{\mathrm{Br}}^{-}}^{o}=+1.09V;$ ${E}_{{\mathrm{Au}}^{3+}/\mathrm{Au}}^{o}=1.4V$ The strongest oxidizing agent is

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Decomposition of $X$ exhibits a rate constant of $0.05 \mu g/\mathrm{year}$. How many years are required for the decomposition of $5 \mu g$ of $X$ into $2.5 \mu g$?

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If solubility product of $Z{r}_{3}{(P{O}_{4})}_{4}$ is denoted by ${K}_{sp}$ and its molar solubility is denoted by $S$ , then which of the following relation between $S$ and ${K}_{sp}$ is correct?

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A $10 \mathrm{mg}$ effervescent tablet containing sodium bicarbonate and oxalic acid releases $0.25 \mathrm{~mL}$ of $\mathrm{CO}_{2}$ at $\mathrm{T}=298.15 \mathrm{~K}$ and $\mathrm{P}=1$ bar. If molar volume of $\mathrm{CO}_{2}$ is $25.0 \mathrm{~L}$ under such condition, what is the percentage of sodium bicarbonate in each tablet? [Molar mass of $\left.\mathrm{NaHCO}_{3}=84 \mathrm{~g} \mathrm{~mol}^{-1}\right]$

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Given: $C{o}^{3+}+{e}^{-}\rightarrow C{o}^{2+};E^{\circ}=+1.81V$ ${Pb}^{3+}+{2e}^{-}\rightarrow {Pb}^{2+};E^{\circ}=+1.67V$ $C{e}^{4+}+{e}^{-}\rightarrow C{e}^{3+};E^{\circ}=+1.61V$ ${Bi}^{3+}+{3e}^{-}\rightarrow Bi;E^{\circ}=+0.20V$ Oxidizing power of the species will increase in the order:

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For the equilibrium $2 \mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{H}_{3} \mathrm{O}^{+}+\mathrm{OH}^{-} ;$ the value of $\Delta \mathrm{G}^{\circ}$ at $298 \mathrm{~K}$ is approximately:

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For the reaction, $2A+B\rightarrow$ products, when the concentration of $A$ and $B$ both were doubled, the rate of the reaction increased from $0.3 mol {L}^{-1}{s}^{-1}$ to $2.4 mol {L}^{-1}{s}^{-1}.$ When the concentration of $A$ alone is doubled, the rate increased from $0.3 mol {L}^{-1}{s}^{-1}$ to $0.6 mol {L}^{-1}{s}^{-1}.$ Which one of the following statements is correct?

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The molar solubility of $Cd{(OH)}_{2}$ is $1.84\times {10}^{-5}M$ in water. The expectes solunility of $Cd{(OH)}_{2}$ in a buffer solution of $pH=12$ is:

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A process will be spontaneous at all temperatures if:

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The de Broglie wavelength $(\lambda)$ associated with a photoelectron varies with the frequency $(v)$ of the incident radiation as,$\left[v_{0}\right.$ is threshold frequency]:

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The difference between $\Delta H$ and $\Delta U$ is $(\Delta H-\Delta U)$, when the combustion of one mole of heptane $(l)$ is carried out at a temperature $T$ , is equal to:

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