JEE Main 2017 — Physical Chemistry

The rate of a reaction quadruples when the temperature changes from $300$ to $310K$ . The activation energy of this reaction is: (Assume Activation energy and pre-exponential factor are independent of temperature; $\mathrm{ln}(2)=0.693;R=8.314J{\mathrm{mol}}^{-1}{K}^{-1}$)

Among the following species which option contains all isoelectronic species?

Consider the following standard electrode potentials (${\text{E}}^{\text{o}}$ in volts) in aqueous solution: $\begin{matrix}\underset{}{\text{E}\text{l}\text{e}\text{m}\text{e}\text{n}\text{t}} & \underset{}{{\text{M}}^{3+}/\text{M}} & \underset{}{{\text{M}}^{+}/\text{M}} \\ \text{A}\text{l} & -1.66 & +0.55 \\ \text{T}\text{l} & +1.26 & -0.34\end{matrix}$ Based on these data, which of the following statements is correct?

Which of the following ions does not liberate hydrogen gas on reaction with dilute acids?

The pair of compounds having metals in their highest oxidation state is

$\text{Δ}\text{U}$ is equal to:

$5g$ of ${\mathrm{Na}}_{2}{\mathrm{SO}}_{4}$ was dissolved in $x g$ of ${H}_{2}O$ . The change in freezing point was found to be $3{.82}^{o}C$ . If ${\mathrm{Na}}_{2}{\mathrm{SO}}_{4}$ is $81.5%$ ionised, the value of $x$ ( ${K}_{f}$ for water $=1{.86}^{o}C \mathrm{kg} {\mathrm{mol}}^{-1}$ ) is approximately: (molar mass of $S=32 g {\mathrm{mol}}^{-1}$ and that of $\mathrm{Na}=23 g {\mathrm{mol}}^{-1}$ )

The electron in the hydrogen atom undergoes transition from higher orbitals to orbital of radius $211.6\mathrm{pm}$. This transition is associated with

The enthalpy change on freezing of $1\mathrm{mol}$ of water at $5^{\circ}C$ to ice at $-5^{\circ}C$ is: (Given ${\Delta }_{\mathrm{fus}} H=6 \mathrm{kJ} {\mathrm{mol}}^{-1}$ at $0^{\circ}C,$ ${C}_{p}({H}_{2}O, l)=75.3 J {\mathrm{mol}}^{-1}{K}^{-1}$ ${C}_{p}({H}_{2}O, s)=36.8 J {\mathrm{mol}}^{-1}{K}^{-1}$ )

An ideal gas undergoes isothermal expansion at constant pressure. During the process:

A gas undergoes change from state $A$ to state $B$. In this process, the heat absorbed and work done by the gas is $5J\text{and}8J$, respectively. Now gas is brought back to $A$ by another process during which $3J$ of heat is evolved. In this reverse process of $B\mathrm{to}A$.

$50 \mathrm{mL}$ of $0.2M$ ammonia solution is treated with $25\mathrm{mL}\mathrm{of}0.2M\mathrm{HCl}$. If ${\mathrm{pK}}_{b}$ of ammonia solution is $4.75$, the $\mathrm{pH}$ of the mixture will be:

If the shortest wavelength in Lyman series of hydrogen atom is $A$, then the longest wavelength in Paschen series of ${\mathrm{He}}^{+}$ is

The freezing point of benzene decreases by ${0.45}^{^{\circ}}C$ on adding $0.2 g$ of acetic acid to $20g$ of benzene. If acetic acid associates to form a dimer in benzene, then what is the percentage association of acetic acid in benzene? $({K}_{f}\mathrm{for} \mathrm{benzene}=5.12 K \mathrm{kg} {\mathrm{mol}}^{-1} )$

Excess of $\mathrm{NaOH}(\mathrm{aq})$ was added to $100\mathrm{mL}$ of ${\mathrm{FeCl}}_{3} (\mathrm{aq})$ resulting into $2.14g$ of $\mathrm{Fe}{(\mathrm{OH})}_{3}$. The molarity of ${\mathrm{FeCl}}_{3}(\mathrm{aq})$ is: (Given the molar mass of$\mathrm{Fe}=56g$${\mathrm{mol}}^{-1}$ and molar mass of $\mathrm{Cl}=35.5 g {\mathrm{mol}}^{-1}$)

To find the standard potential of ${M}^{3+}/M$ electrode, the following cell is constituted: $\mathrm{Pt}/M/{M}^{3+} (0.001 \mathrm{mol} {L}^{-1})/{\mathrm{Ag}}^{+} (0.01 \mathrm{mol} {L}^{-1})/\mathrm{Ag}$ The emf of the cell is found to be $0.421\mathrm{volt}$ at $298K$. The standard potential of half-reaction ${M}^{3+}+3{e}^{-}\rightarrow M$ at $298K$ will be: (Given: ${E}_{\frac{{\mathrm{Ag}}^{+}}{\mathrm{Ag}}}^{\circleddash }$ at $298K=0.80\mathrm{volt}$)

Two reactions ${A}_{1}$ and ${A}_{2}$ have identical pre-exponential factors. The activation energy of ${A}_{1}$ is more than ${A}_{2}$ by $10\mathrm{kJ}{\mathrm{mol}}^{-1}$ . If ${k}_{1}$ and ${k}_{2}$ are the rate constants for reactions ${A}_{1}$ and ${A}_{2}$, respectively at $300K$, then $\mathrm{ln}⁡(\frac{{k}_{2}}{{k}_{1}})$ is equal to $(R=8.314 J {\mathrm{mol}}^{-1}{K}^{-1})$

$1$ gram of a carbonate $({M}_{2}{\mathrm{CO}}_{3})$ on treatment with excess $\mathrm{HCl}$ produces $0.01186$ moles of ${\mathrm{CO}}_{2}$ . The molar mass of ${M}_{2}{\mathrm{CO}}_{3}$ in ${\mathrm{gmol}}^{-1}$ is:

For a reaction, $A(g)\rightarrow A(l);\Delta H=-3\mathrm{RT}.$ The correct statement for the reaction is

Given: $C(\mathrm{graphite})+{O}_{2}(g)\rightarrow {\mathrm{CO}}_{2}(g) ;{\Delta }_{r}{H}^{o}=-393.5\mathrm{kJ}{\mathrm{mol}}^{-1}$ ${H}_{2}(g)+\frac{1}{2}{O}_{2}(g)\rightarrow {H}_{2}O(l);{\Delta }_{r}{H}^{o}=-285.8 \mathrm{kJ} {\mathrm{mol}}^{-1}$ ${\mathrm{CO}}_{2}(g)+2{H}_{2}O(l)\rightarrow {\mathrm{CH}}_{4}(g)+2{O}_{2}(g);{\Delta }_{r}{H}^{o}=+890.3 \mathrm{kJ} {\mathrm{mol}}^{-1}$ Based on the above thermochemical equations, the value of ${\Delta }_{r}{H}^{o}$ at $298K$ for the reaction $C(\mathrm{graphite})+2{H}_{2}(g)\rightarrow {\mathrm{CH}}_{4}(g)$ will be:

Given ${E}_{{\mathrm{Cl}}_{2}/{\mathrm{Cl}}^{-}}^{o}=1.36V, {E}_{{\mathrm{Cr}}^{3+}/\mathrm{Cr}}^{o}= -0.74V$ ${E}_{{\mathrm{Cr}}_{2}{O}_{7}^{2-}/{\mathrm{Cr}}^{3+}}^{o}=1.33V, {E}_{{\mathrm{MnO}}_{4}^{-}/{\mathrm{Mn}}^{2+}}^{o}=1.51V.$ Among the following, the strongest reducing agent is:

The radius of the second Bohr orbit for hydrogen atom is (Planck's constant, $(h)=6.6262\times {10}^{-34}\mathrm{Js};$ mass of electron $=9.1091\times {10}^{-31}\mathrm{kg};$ charge of electron $=1.60210\times {10}^{-19}C;$ permittivity of vacuum, $({\in }_{0})=8.854185\times {10}^{-12}{\mathrm{kg}}^{-1}{m}^{-3}{A}^{2}$)

The rate of a reaction A doubles on increasing the temperature from$300\mathrm{to}310K$. By how much, the temperature of reaction B should be increased from $300K$ so that rate doubles if activation energy of the reaction B is twice to that of reaction A.

The following reaction occurs in the Blast Furnace where iron ore is reduced to iron metal: $\text{F}{\text{e}}_{2}{\text{O}}_{3}(\text{s})+3\text{C}\text{O}(\text{g}) \rightleftharpoons 2\text{F}\text{e} (\text{l})+3\text{C}{\text{O}}_{2}(\text{g})$ Using the Le Chatelier's principle, predict which one of the following will not disturb the equilibrium?

A solution is prepared by mixing $8.5$ g of ${\mathrm{CH}}_{2}{\mathrm{Cl}}_{2}$ and $11.95 \text{g}$ of ${\mathrm{CHCl}}_{3}$ . If vapour pressure of ${\mathrm{CH}}_{2}{\mathrm{Cl}}_{2}$ and ${\mathrm{CHCl}}_{3}$ at $298$K are $415$ and $200$ mm Hg respectively, the mole fraction of ${\mathrm{CHCl}}_{3}$ in vapour form is: $(\text{M}\text{o}\text{l}\text{a}\text{r} \text{m}\text{a}\text{s}\text{s} \text{o}\text{f} \mathrm{Cl}=35.5 \text{g} \text{m}\text{o}{\text{l}}^{-1})$

Addition of sodium hydroxide solution to a weak acid (HA) results in a buffer of pH 6. If ionization constant of HA is ${10}^{-5}$, the ratio of salt to acid concentration in the buffer solution will be:

What quantity (in $\mathrm{mL}$) of a $45%$ acid solution of a mono-protic strong acid must be mixed with a $20%$ solution of the same acid to produce $800\mathrm{mL}$ of a $29.875%$ acid solution?

What is the standard reduction potential $({E}^{o})$ for ${\mathrm{Fe}}^{3+}\rightarrow \mathrm{Fe}?$ Given that: ${\mathrm{Fe}}^{2+}+2{e}^{-}\rightarrow \mathrm{Fe};{E}_{{\mathrm{Fe}}^{2+}/\mathrm{Fe}}^{o}=-0.47V$ ${\mathrm{Fe}}^{3+}+{e}^{-}\rightarrow {\mathrm{Fe}}^{2+};{E}_{{\mathrm{Fe}}^{3+}/{\mathrm{Fe}}^{2+}}^{o}=+0.77V$

The most abundant elements by mass in the body of a healthy human adult are: Oxygen (61.4%); Carbon (22.9%), Hydrogen (10.0%); and Nitrogen (2.6%). The weight which a 75kg person would gain if all ${ }^{1}H$ atoms are replaced by ${ }^{2}H$ atoms is:

${ \text{pK}}_{\text{a}}$ of a weak acid $( \text{HA})$ and ${ \text{pK}}_{\text{b}}$ of a weak base $( \text{BOH})$ are $3.2$ and $3.4$ respectively. The $\text{pH}$ of their salt $( \text{AB})$ solution at ${ \text{25}}^{\text{o}} \text{C}$ is