Physical Chemistry PYQ — Page 4

How many grams of residue is obtained by heating $2.76$ g of silver carbonate?<br>(Given: Molar mass of C, O and Ag are $12$, $16$ and $108$ g mol$^{-1}$ respectively)

Consider the following two half-cell reactions along with the standard reduction potential given: $CO_2 + 6H^+ + 6e^- \rightarrow CH_3 OH + H_2 O \quad E°_{red} = 0.02$ V $\dfrac{1}{2} O_2 + 2H^+ + 2e^- \rightarrow H_2 O \quad E°_{red} = 1.23$ V A fuel cell was set up using the above two reactions such that the cell operates under the standard condition of $1$ bar pressure and $298$ K temperature. The fuel cell works with $80\%$ efficiency. If the work derived from the cell using $1$ mol of $CH_3 OH$ is used to compress an ideal gas isothermally against a constant pressure of $1$ kPa, then the change in the volume of the gas, $\Delta V = $ _____ m$^3$. (nearest integer) Given: $F = 96500$ C mol$^{-1}$

The wavelength of spectral line obtained in the spectrum of $\mathrm{Li}^{2+}$ ion, when the transition takes place between two levels whose sum is 4 and difference is 2, is

The pH of a solution obtained by mixing $5$ mL of $0.1$ M $NH_4OH$ solution with $250$ mL of $0.1$ M $NH_4Cl$ solution is _____ $\times 10^{-2}$. (Nearest integer) Given: $pK_b(NH_4OH) = 4.74$ $\log 2 = 0.30$ $\log 3 = 0.48$ $\log 5 = 0.70$

$\mathrm{A}+2 \mathrm{~B} \longrightarrow \mathrm{AB}_{2}$<br>36.0 g of 'A' (Molar mass: $60 \mathrm{~g} \mathrm{~mol}^{-1}$) and 56.0 g of ' $\mathrm{B}^{\prime}$ (Molar mass: $80 \mathrm{~g} \mathrm{~mol}^{-1}$) are allowed to react. Which of the following statements are correct ?<br>A. 'A' is the limiting reagent.<br>B. $77.0 \mathrm{~g}$ of $\mathrm{AB}_{2}$ is formed.<br>C. Molar mass of $A B_{2}$ is $140 \mathrm{~g} \mathrm{~mol}^{-1}$.<br>D. $15.0 \mathrm{~g}$ of A is left unreacted after the completion of reaction.<br>Choose the correct answer from the options given below :

MX is a sparingly soluble salt that follows the given solubility equilibrium at 298 K. $\mathrm{MX}(\mathrm{s}) \rightleftharpoons \mathrm{M}^{+}(\mathrm{aq})+\mathrm{X}^{-}(\mathrm{aq}) ; \mathrm{K}_{\mathrm{sp}}=10^{-10}$ If the standard reduction potential for $\mathrm{M}^{+}(\mathrm{aq}) \xrightarrow{+\mathrm{e}^{-}} \mathrm{M}(\mathrm{s})$ is $\left(\mathrm{E}_{\mathrm{M}^{+} / \mathrm{M}}^{\ominus}\right)=0.79 \mathrm{~V}$, then the value of the standard reduction potential for the metal/metal insoluble salt electrode $\mathrm{E}_{\mathrm{X}^{-} / \mathrm{MX}(\mathrm{s}) / \mathrm{M}}^{\ominus}$ is $\_\_\_\_$ mV. (nearest integer) [Given : $\frac{2.303 \mathrm{RT}}{\mathrm{F}}=0.059 \mathrm{~V}$ ]

Which of the following graphs between pressure ' p ' versus volume ' V ' represents the maximum work done?

Match the LIST-I with LIST-II <table class="pyq-table"><tbody><tr><th>List-I Orbital</th><th>List-II Radial nodes and nodal plane</th></tr><tr><td>A. $2s$</td><td>I. $1$ Radial node + two nodal planes</td></tr><tr><td>B. $3s$</td><td>II. $1$ Radial node + one nodal plane</td></tr><tr><td>C. $3p$</td><td>III. $2$ Radial nodes + No nodal plane</td></tr><tr><td>D. $4d$</td><td>IV. $1$ Radial node + No nodal plane</td></tr></tbody></table> Choose the correct answer from the options given below:

The correct order of total number of atoms present in (A) $2$ moles of cyclohexane (B) $684$ g of sucrose (C) $90.8$ L of dihydrogen at STP is:

Two liquids A and B form an ideal solution. At 320 K, the vapour pressure of the solution, containing 3 mol of A and 1 mol of B is 500 mm Hg. At the same temperature, if 1 mol of A is further added to this solution, vapour pressure of the solution increases by 20 mm Hg. Vapour pressure (in mm Hg) of B in pure state is $\_\_\_\_$. (Nearest integer)

Given below are two statements : Statement (I) : 1,2,3-Trihydroxypropane can be separated from water by simple distillation. Statement (II) : An azeotropic mixture cannot be separated by fractional distillation. In the light of the above statements, choose the correct answer from the options given below :

Match List - I with List - II. Given $V_1$ and $V_2$ are initial and final volumes respectively.<table class="pyq-table"><tbody><tr><th>List - I (Isothermal process)</th><th>List - II (Expression)</th></tr><tr><td>A. Reversible expansion</td><td>I. $q = 0$</td></tr><tr><td>B. Free expansion</td><td>II. $q = nRT \ln\dfrac{V_2}{V_1}$</td></tr><tr><td>C. Irreversible Compression</td><td>III. $w = -p_{ext}(V_1 - V_2)$</td></tr><tr><td>D. Cyclic reversible</td><td>IV. $\dfrac{q_{rev}}{T} = 0$</td></tr></tbody></table>Choose the correct answer from the options given below :

In the reaction, $2 \mathrm{Al}(\mathrm{s})+6 \mathrm{HCl}(\mathrm{aq}) \rightarrow 2 \mathrm{Al}^{3+}(\mathrm{aq})+6 \mathrm{Cl}^{-}(\mathrm{aq})+3 \mathrm{H}_{2}(\mathrm{~g})$

At $27^{\circ} \mathrm{C}$ in presence of a catalyst, activation energy of a reaction is lowered by $10 \mathrm{~kJ} \mathrm{~mol}^{-1}$. The logarithm of ratio of $\frac{\mathrm{k} \text { (catalysed) }}{\mathrm{k} \text { (uncatalysed) }}$ is.... (Consider that the frequency factor for both the reactions is same)

What volume of hydrogen gas at STP would be liberated by action of $50\text{ mL}$ of $H_2SO_4$ of $50\%$ purity (density $= 1.3\text{ g mL}^{-1}$) on $20\text{ g}$ of zinc ? Given : Molar mass of H, O, S, Zn are $1, 16, 32, 65\text{ g mol}^{-1}$ respectively.

One mole each of He and $A(g)$ are taken in a $10$ L closed flask and heated to $400$ K to establish the following equilibrium. $A(g) \rightleftharpoons B(g)$. $K_c$ for this reaction at $400$ K is $4.0$. The partial pressures (in atm) of He and $B(g)$ are respectively (at equilibrium) (Assume He, $A(g)$ and $B(g)$ behave as ideal gases) (Given: $R = 0.082$ L atm K$^{-1}$ mol$^{-1}$)

A volume of $x\,\mathrm{mL}$ of $5\,\mathrm{M}\,\mathrm{NaHCO_3}$ solution was mixed with $10\,\mathrm{mL}$ of $2\,\mathrm{M}\,\mathrm{H_2CO_3}$ solution to make an electrolytic buffer. If the same buffer was used in the following electrochemical cell to record a cell potential of $235.3\,\mathrm{mV}$, then the value of $x = \_\_\_\_$ mL (nearest integer). $\mathrm{Sn(s)} \; \big| \; \mathrm{Sn(OH)_6^{2-}}(0.5\,\mathrm{M}) \; \big| \; \mathrm{HSnO_2^-}(0.05\,\mathrm{M}) \; \big| \; \mathrm{OH^-} \; \big| \; \mathrm{Bi_2O_3(s)} \; \big| \; \mathrm{Bi(s)}$ Consider up to one place of decimal for intermediate calculations. $\begin{array}{ll}\text{Given:} & E^\circ_{\mathrm{[Sn(OH)_6]^{2-}/HSnO_2^-}} = -0.90\,\mathrm{V} \\[4pt]& E^\circ_{\mathrm{Bi_2O_3/Bi}} = -0.44\,\mathrm{V} \\[4pt]& \mathrm{p}K_a(\mathrm{H_2CO_3}) = 6.11 \\[4pt]& \dfrac{2.303\,RT}{F} = 0.059\,\mathrm{V} \\[6pt]& \text{Antilog}(1.29) = 19.5\end{array}$

Observe the following equilibrium in a 1 L flask. $\mathrm{A}(\mathrm{~g}) \rightleftharpoons \mathrm{B}(\mathrm{~g})$ At $\mathrm{T}(\mathrm{K})$, the equilibrium concentrations of A and B are 0.5 M and 0.375 M respectively. 0.1 moles of A is added into the flask and heated to $\mathrm{T}(\mathrm{K})$ to establish the equilibrium again. The new equilibrium concentrations (in M) of A and B are respectively

Which of the following contain the same number of atoms ? (Given : Molar mass in g mol$^{-1}$ of H, He, O and S are $1, 4, 16$ and $32$ respectively) A. $2$ g of O$_2$ gas B. $4$ g of SO$_2$ gas C. $1400$ mL of O$_2$ at STP D. $0.05$ L of He at STP E. $0.0625$ mol of H$_2$ gas Choose the correct answer from the options given below :

Decomposition of a hydrocarbon follows the equation $k = (5.5 \times 10^{11}\,\text{s}^{-1})\,e^{\frac{-28000\,\text{K}}{T}}$. The activation energy of reaction is __________ kJ mol$^{-1}$. (Nearest Integer) Given : R $= 8.3$ J K$^{-1}$ mol$^{-1}$

Identify the correct statements : A. Hydrated salts can be used as primary standard. B. Primary standard should not undergo any reaction with air. C. Reactions of primary standard with another substance should be instantaneous and stoichiometric. D. Primary standard should not be soluble in water. E. Primary standard should have low relative molar mass. Choose the correct answer from the options given below :

The energy required by electrons, present in the first Bohr orbit of hydrogen atom to be excited to second Bohr orbit is $\_\_\_\_$ $\mathrm{J} \mathrm{mol}^{-1}$. Given: $R_{H}=2.18 \times 10^{-11} \mathrm{ergs}$.

When $0.25$ moles of a non-volatile, non-ionizable solute was dissolved in $1$ mole of a solvent the vapor pressure of solution was $x\%$ of vapor pressure of pure solvent. What is $x\%$?

A monoatomic anion $(A^-)$ has $45$ neutrons and $36$ electrons. Atomic mass, group in the periodic table and physical state at room temperature of the element $(A)$ respectively are