Physical Chemistry PYQ — Page 25

Match List-I with List-II<table class="pyq-table"><tbody><tr><td></td><td>List-I</td><td></td><td>List-II</td></tr><tr><td>A</td><td>$16g$ of ${\mathrm{CH}}_{4}(g)$</td><td>I</td><td>Weighs $28g$</td></tr><tr><td>B</td><td>$1g$ of ${H}_{2}(g)$</td><td>II</td><td>$60.2\times {10}^{23}$ electrons</td></tr><tr><td>C</td><td>$1\mathrm{mole}$ of ${N}_{2}(g)$</td><td>III</td><td>Weighs $32g$</td></tr><tr><td>D</td><td>$0.5\mathrm{mol}$of ${\mathrm{SO}}_{2}(g)$</td><td>IV</td><td>Occupies$11.4L$ volume at STP</td></tr></tbody></table>Choose the correct answer from the options given below:

$25\mathrm{mL}$ of silver nitrate solution $(1M)$ is added dropwise to $25\mathrm{mL}$ of potassium iodide $(1.05M)$ solution. The ion(s) present in very small quantity in the solution is/are

If the boiling points of two solvents $X$ and $Y$ (having same molecular weights) are in the ratio $\text{2: 1}$ and their enthalpy of vaporizations are in the ratio $1:2$, then the boiling point elevation constant of $X$ is $m$ times the boiling point elevation constant of $Y$. The value of $m$ is (nearest integer).

The titration curve of weak acid vs. strong base with phenolphthalein as indicator is shown below. The ${K}_{\text{phenolphthalein }}=4\times {10}^{-10}$ Given: $\mathrm{log}2=0.3$  The number of following statement/s which is/are correct about phenolphthalein is _______ A. It can be used as an indicator for the titration of weak acid with weak base. B. It begins to change colour at $\mathrm{pH}=8.4$ C. It is a weak organic base D. It is colourless in acidic medium

When 2 litre of ideal gas expands isothermally into vacuum to a total volume of $6$ litre, the change in internal energy is _____ J. (Nearest integer)

Lead storage battery contains $38%$ by weight solution of ${H}_{2}{\mathrm{SO}}_{4}$. The van't Hoff factor is $2.67$ at this concentration. The temperature in Kelvin at which the solution in the battery will freeze is _____ (Nearest integer). Given ${K}_{f}=1.8K\mathrm{kg}{\mathrm{mol}}^{-1}$

$25\mathrm{mL}$ of an aqueous solution of $\mathrm{KCl}$ was found to require $20\mathrm{mL}$ of $1M{\mathrm{AgNO}}_{3}$ solution when titrated using ${K}_{2}{\mathrm{CrO}}_{4}$ as an indicator. What is the depression in freezing point of $\mathrm{KCl}$ solution of the given concentration? (Nearest integer). (Given : ${K}_{f}=2.0K\mathrm{kg}{\mathrm{mol}}^{-1}$ ) Assume 1) $100%$ ionization and 2) density of the aqueous solution as $1g{\mathrm{mL}}^{-1}$

The volume of $\mathrm{HCl}$, containing $73g{L}^{-1}$, required to completely neutralise $\mathrm{NaOH}$ obtained by reacting $0.69g$ of metallic sodium with water, is _____ $\mathrm{mL}$. (Nearest Integer) (Given : molar Masses of $\mathrm{Na},\mathrm{Cl},O,H$ are $23,35.5,16$ and $1g{\mathrm{mol}}^{-1}$ respectively)

The total pressure of a mixture of non-reacting gases $X(0.6g)$ and $Y(0.45g)$ in a vessel is $740\mathrm{mm}$ of $\mathrm{Hg}$. The partial pressure of the gas $X$ is $\mathrm{mm}$ of $\mathrm{Hg}.$ (Nearest Integer) (Given : molar mass $X=20$ and $Y=45g{\mathrm{mol}}^{-1}$ )

$1$ mole of ideal gas is allowed to expand reversibly and adiabatically from a temperature of $27^{\circ}C$. The work done is $3\mathrm{kJ}{\mathrm{mol}}^{-1}$. The final temperature of the gas is _____ $K$ (Nearest integer). Given ${C}_{v}=20J{\mathrm{mol}}^{-1}{K}^{-1}$

The shortest wavelength of hydrogen atom in Lyman series is $\lambda$. The longest wavelength in Balmer series of ${\mathrm{He}}^{+}$ is

The Total pressure observed by mixing two liquid $A\text{and}B$ is $350\mathrm{mm}\mathrm{Hg}$ when their mole fractions are $0.7\text{and}0.3$ respectively. The Total pressure becomes$410\mathrm{mm}\mathrm{Hg}$ if the mole fractions are changed to$0.2\text{and}0.8$ respectively for $A\text{and}B$. The vapour pressure of pure $A$ is ______ $\mathrm{mm}\mathrm{Hg}$. (Nearest integer) Consider the liquids and solutions behave ideally

A first order reaction has the rate constant, $k=4.6\times {10}^{-3}{s}^{-1}$. The number of correct statement/s from the following is/are Given: $\mathrm{log}3=0.48$. A. Reaction completes in $1000s$. B. The reaction has a half-life of $500s$. C. The time required for $10%$ completion is 25 times the time required for 90% completion. D. The degree of dissociation is equal to $(1-{e}^{-\mathrm{kt}})$. E. The rate and the rate constant have the same unit.

Solid Lead nitrate is dissolved in $1$ litre of water. The solution was found to boil at $100.15^{\circ}C$. When $0.2\mathrm{mol}$ of $\mathrm{NaCl}$ is added to the resulting solution, it was observed that the solution froze at $-0.8^{\circ}C$. The solutbility product of ${\mathrm{PbCl}}_{2}$ formed is _____ $\times {10}^{-6}$ at $298K$. (Nearest integer) Given : ${K}_{b}=0.5K\mathrm{kg}{\mathrm{mol}}^{-1}$ and ${K}_{f}=1.8\mathrm{kg}{\mathrm{mol}}^{-1}$. Assume molality to be equal to molarity in all cases.

The number of incorrect statement/s about the black body from the following is______ (A) Emit or absorb energy in the form of electromagnetic radiation. (B) Frequency distribution of the emitted radiation depends on temperature. (C) At a given temperature, intensity vs frequency curve passes through a maximum value. (D) The maximum of the intensity vs frequency curve is at a higher frequency at higher temperature compared to that at lower temperature.

What is the mass ratio of ethylene glycol (${C}_{2}{H}_{6}{O}_{2}$, molar mass $=62g/\mathrm{mol}$) required for making $500g$ of $0.25$ molal aqueous solution and $250\mathrm{mL}$ of $0.25$ molar aqueous solution?

During the reaction of permanganate with thiosulphate, the change in oxidation of manganese occurs by value of $3$. Identify which of the below medium will favour the reaction.

For reaction: ${\mathrm{SO}}_{2}(g)+\frac{1}{2}{O}_{2}(g)\rightleftharpoons {\mathrm{SO}}_{3}(g)$ ${K}_{P}=2\times {10}^{12}$ at $27^{\circ}C$ and $1\mathrm{atm}$ pressure. The ${K}_{c}$ for the same reaction is $\times {10}^{13}.($ Nearest integer) (Given $R=0.082L\mathrm{atm}{K}^{-1}{\mathrm{mol}}^{-1}$ )

$1\times {10}^{-5}M{\mathrm{AgNO}}_{3}$ is added to $1L$ of saturated solution of $\mathrm{AgBr}$. The conductivity of this solution at $298K$ is $_______\times {10}^{-8}S{m}^{-1}$. [Given : ${K}_{\mathrm{sp}}(\mathrm{AgBr})=4.9\times {10}^{-13}$ at $298K$ ${\lambda }_{{\mathrm{Ag}}^{+}}^{0}=6\times {10}^{-3}{\mathrm{Sm}}^{2}{\mathrm{mol}}^{-1}$ ${\lambda }_{{\mathrm{Br}}^{-}}^{0}=8\times {10}^{-3}{\mathrm{Sm}}^{2}{\mathrm{mol}}^{-1}$ ${\lambda }_{{\mathrm{NO}}_{3}^{-}}^{0}=7\times {10}^{-3}{\mathrm{Sm}}^{2}{\mathrm{mol}}^{-1}]$

A metal surface of $100{\mathrm{cm}}^{2}$ area has to be coated with nickel layer of thickness $0.001\mathrm{mm}.$ A current of $2A$ was passed through a solution of $\mathrm{Ni}{({\mathrm{NO}}_{3})}_{2}$ for $‘x’$ seconds to coat the desired layer. The value of $x$ is _________. (Nearest integer) ($\rho Ni$ (density of Nickel) is $10g{\mathrm{mL}}^{–1},$Molar mass of Nickel is $60g{\mathrm{mol}}^{-1}F=96500{\mathrm{Cmol}}^{-1}$)

The number of pairs of the solution having the same value of the osmotic pressure from the following is (Assume $100%$ ionization) A. $0.500M{C}_{2}{H}_{5}\mathrm{OH}(\mathrm{aq})$ and $0.25M\mathrm{KBr}(\mathrm{aq})$ B. $0.100{M}_{}{K}_{4}[\mathrm{Fe}(\mathrm{CN}{)}_{6}](\mathrm{aq})$ and $0.100M$ ${\mathrm{FeSO}}_{4}{({\mathrm{NH}}_{4})}_{2}{\mathrm{SO}}_{4}(\mathrm{aq})$ C. $0.05M{K}_{4}[\mathrm{Fe}(\mathrm{CN}{)}_{6}]$ (aq) and $0.25M\mathrm{NaCl}$ $(\mathrm{aq})$ D. $0.15M\mathrm{NaCl}(\mathrm{aq})$ and $0.1M{\mathrm{BaCl}}_{2}(\mathrm{aq})$ E. $0.02M\mathrm{KCl}.{\mathrm{MgCl}}_{2}.6{H}_{2}O(\mathrm{aq})$ and $0.05M$ $\mathrm{KCl}(\mathrm{aq})$

For a concentrated solution of a weak electrolyte (${K}_{\mathrm{eq}}=$equilibrium constant) ${A}_{2}{B}_{3}$ of concentration $‘C’,$ the degree of dissociation $‘\alpha ’$ is

For lead storage battery pick the correct statements A. During charging of battery, ${\mathrm{PbSO}}_{4}$ on anode is converted into ${\mathrm{PbO}}_{2}$ B. During charging of battery, ${\mathrm{PbSO}}_{4}$ on cathode is converted into ${\mathrm{PbO}}_{2}$ C. Lead storage battery consists of grid of lead packed with ${\mathrm{PbO}}_{2}$ as anode D. Lead storage battery has $~38%$ solution of sulphuric acid as an electrolyte Choose the correct answer from the options given below:

 The electron in the ${n}^{\mathrm{th}}$ orbit of ${\mathrm{Li}}^{2+}$ is excited to $(n+1)$ orbit using the radiation of energy $1.47\times {10}^{-17}J$ (as shown in the diagram). The value of $n$ is ___________ Given : ${R}_{H}=2.18\times {10}^{-18}J$