JEE Main Chemistry — Physical Chemistry previous year questions with solutions.
Which one of the following about an electron occupying the 1s orbital in a hydrogen atom is incorrect? (The Bohr radius is represented by ${a}_{0}$ ).
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:
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)
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? $\left[\mathrm{R}_{\mathrm{H}}=1 \times 10^{5} \mathrm{~cm}^{-1} \cdot \mathrm{h}=6.6 \times 10^{-34} \mathrm{Js}, \mathrm{c}=3 \times 10^{8} \mathrm{~ms}^{-1}\right]$
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:
Among the following, the energy of $2s$ orbital is lowest in:
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:
Which one of the following graphs between molar conductivity $({\Lambda }_{m})$ versus $\sqrt{C}$ is correct?
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 :
The $pH$ of a $0.02 M$ $N{H}_{4}Cl$ solution will be [Given: ${K}_{b}(N{H}_{4}OH)={10}^{-5}$ and $\mathrm{log}2=0.301$]
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:
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.
For the following reaction, the mass of water produced from $445 g$ of ${C}_{57}{H}_{110}{O}_{6}$ is: $2 {C}_{57}{H}_{110}{O}_{6}(s)+163{O}_{2}(g)\rightarrow 114 {\mathrm{CO}}_{2}(g)+110{H}_{2}O(l)$
$8 g$ 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:
In which one of the following equilibria, ${K}_{p}\neq {K}_{c}?$
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 $\mathrm{Ca}{(\mathrm{OH})}_{2}\mathrm{is} 5.5\times {10}^{-6}$)
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 $=122 {\mathrm{gmol}}^{-1})$
The standard Gibbs energy for the given cell reaction in $kJ mo{l}^{-1}$ at $298 K$ is: $Zn(s)+C{u}^{2+}(aq)\longrightarrow Z{n}^{2+}(aq)+Cu(s)$ , ${E}^{0}=2 V at 298 K$ $(Faraday's constant ,F=96000 C mo{l}^{-1})$
$5$ 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:
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:
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)
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 $\left.\mathrm{NaHCO}_{3}=84 \mathrm{~g} \mathrm{~mol}^{-1}\right]$
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?
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.