Physical Chemistry PYQ — Page 48

${N}_{2}{O}_{5(g)}\rightarrow 2{\mathrm{NO}}_{2(g)}+\frac{1}{2}{O}_{2(g)}$ In the above first order reaction the initial concentration of ${N}_{2}{O}_{5}$ is $2.40\times {10}^{-2}\mathrm{mol}{L}^{-1}$ at $318K.$ The concentration of ${N}_{2}{O}_{5}$ after $1$ hour was $1.60$$\times {10}^{-2}\mathrm{mol}{L}^{-1}.$ The rate constant of the reaction at $318K$ is $\times {10}^{-3}{\mathrm{min}}^{-1}$ (Nearest integer): $[$ Given $:\mathrm{log}3=0.477,\mathrm{log}5=0.699]$

Outermost electronic configuration of a group $13$ element, $E,$ is $4{s}^{2},4{p}^{1}.$ The electronic configuration of an element of p-block period-five placed diagonally to element, $E$ is:

$0.4g$ mixture of $\mathrm{NaOH},{\mathrm{Na}}_{2}{\mathrm{CO}}_{3}$ and some inert impurities was first titrated with $\frac{N}{10}\mathrm{HCl}$ using phenolphthalein as an indicator, $17.5\mathrm{mL}$ of $\mathrm{HCl}$ was required at the end point. After this methyl orange was added and titrated. $1.5\mathrm{mL}$ of same $\mathrm{HCl}$ was required for the next end point. The weight percentage of ${\mathrm{Na}}_{2}{\mathrm{CO}}_{3}$ in the mixture is (Rounded-off to the nearest integer)

Given below are two statements: Statement I : The limiting molar conductivity of $\mathrm{KCl}$ (strong electrolyte) is higher compared to that of $\mathrm{CH}_{3} \mathrm{COOH}$ (weak electrolyte). Statement II : Molar conductivity decreases with decrease in concentration of electrolyte. In the light of the above statements, choose the most appropriate answer from the options given below:

When $12.2g$ of benzoic acid is dissolved in $100g$ of water, the freezing point of solution was found to be $-0.93^{\circ}C({K}_{f}({H}_{2}O)=1.86K\mathrm{kg}{\mathrm{mol}}^{-1})$. The number $(n)$ of benzoic acid molecules associated (assuming $100%$ association) is _.

______grams of $3-$Hydroxy propanal $(\mathrm{MW}=74)$ must be dehydrated to produce $7.8g$ of acrolein $(\mathrm{MW}=56)({C}_{3}{H}_{4}O)$ if the percentage yield is $64.$ (Round off to the Nearest Integer). $[\text{Given: Atomic masses}:C:12.0u,H:1.0u,O:16.0u]$

It is true that:

The figure that is not a direct manifestation of the quantum nature of atom is :

The volume $(inmL)$ of $0.125M{AgNO}_{3}$ required to quantitatively precipitate chloride ions in $0.3g$ of $[Co{(N{H}_{3})}_{6}]C{l}_{3}$ is __________. $[Co{(N{H}_{3})}_{6}]MC{l}_{3}=267.46g/mol$ ${AgNOM}_{3}=169.87g/mol$ Report the nearest integer as the answer.

The unit of rate constant for a zero order reaction is:

According to Raoults law, the relative lowering of vapor pressure of a solution is equal to:

The true statement amongst the following is:

The strengths of $5.6$ volume hydrogen peroxide (of density $1g/\mathrm{mL}$ ) in terms of mass percentage and molarity$(M)$ respectively, are: (Take molar mass of hydrogen peroxide as $34g/\mathrm{mol}$)

Amongst the following, the form of water with the lowest ionic conductance at $298K$ is:

The difference between the radii of ${3}^{\mathrm{rd}}$ and ${4}^{\text{th }}$ orbits of ${L}_{i}^{2+}$ is ${\Delta R}_{1}$. The difference between the radii of ${3}^{\mathrm{rd}}$ and ${4}^{\text{th }}$ orbits of ${\mathrm{He}}^{+}$ $\Delta {R}_{2}.$ Ratio $\Delta {R}_{1}:\Delta {R}_{2}$ is :

$108 g$ of silver (molar mass $108 g{mol}^{-1}$ ) is deposited at cathode from ${AgNO}_{3}(aq)$ solution by a certain quantity of electricity. The volume (in $L$ ) of oxygen gas produced at $273 K$ and $1$ bar pressure from water by the same quantity of electricity is ________

At $300K$, the vapour pressure of a solution containing $1$ mole of $n$ -hexane and $3$ moles of $n$ -heptane is $550\mathrm{mm}$ of $\mathrm{Hg}$. At the same temperature, if one more mole of $n$ -heptane is added to this solution, the vapour pressure of the solution increases by $10\mathrm{mm}$ of $\mathrm{Hg}$. What is the vapour pressure in $\mathrm{mmHg}$ of $n$ - heptane in its pure state______?

The ${K}_{sp}$ for the following dissociation is $1.6\times {10}^{-5}$ ${PbCl}_{2(s)}\rightleftharpoons P{b}_{(aq)}^{2+}+2C{l}_{(aq)}^{-}$ Which of the following choices is correct for a mixture of $300mL 0.134 MPb{(N{O}_{3})}_{2}$ and $100mL$ $0.4 M NaCl?$

For the reaction ${\mathrm{Fe}}_{2}N(s)+\frac{3}{2}{H}_{2}(g)\rightleftharpoons 2\mathrm{Fe}(s)+{\mathrm{NH}}_{3}(g)$

For the following Assertion and Reason, the correct option is: Assertion: The $pH$ of water increases with increase in temperature. Reason: The dissociation of water into ${H}^{+}$ and $O{H}^{-}$ is an exothermic reaction.

Among $(a)-(d),$ the complexes that can show geometrical isomerism are: $(a)$ ${[Pt{(N{H}_{3})}_{3}Cl]}^{+}$ $(b)$ ${[Pt(N{H}_{3})C{l}_{5}]}^{-}$ $(c)$ $[Pt{(N{H}_{3})}_{2}Cl(N{O}_{2})]$ $(d)$ ${[Pt{(N{H}_{3})}_{4}ClBr]}^{2+}$

For the following reactions $\text{A}\overset{700\text{K}}{\rightarrow }\text{Product}$ $\text{A}\overset{500\text{K}}{\underset{\text{catalyst}}{\rightarrow }}\text{Product}$ It was found that the ${E}_{a}$ is decreased by $30 KJ/mol$ in the presence of catalyst. If the rate remains unchanged, the activation energy for catalysed reaction is (Assume pre-exponential factor is same)

If enthalpy of atomization for $B{r}_{2}(l)$ is $x kJ/mol$ and bond enthalpy for $B{r}_{2}$ is $y kJ/mol$, the relation between them

The size of a raw mango shrinks to a much smaller size when kept in a concentrated salt solution. Which one of the following process can explain this?