Physical Chemistry PYQ — Page 64

For the non-stoichiometry reaction, $2 \text{A} + \text{B} \rightarrow \text{C} + \text{D}$, the following kinetic data were obtained in three separate experiments, all at $298K$.<table class="pyq-table"><tbody><tr><th>Initial Concentration (A)</th><th>Initial Concentration (B)</th><th>Initial rate of formation of C $( {\text{mol L}}^{-} {S}^{-} )$</th></tr><tr><td>$\text{0.1 M}$</td><td>$\text{0.1 M}$</td><td>$\text{1.2} \times 1 {0}^{ - 3 }$</td></tr><tr><td>$\text{0.1 M}$</td><td>$\text{0.2 M}$</td><td>$\text{1.2} \times 1 {0}^{ - 3 }$</td></tr><tr><td>$\text{0.2 M}$</td><td>$\text{0.1 M}$</td><td>$\text{2.4} \times 1 {0}^{ - 3 }$</td></tr></tbody></table> The rate law for the formation of $C$ is

Given below are the half - cell reactions : $\begin{matrix} {\text{Mn}}^{ 2 + } + 2 {\text{e}}^{-} \rightarrow \text{Mn} ; & {\text{E}}^{\circ } = - \text{1.18 V} \\ 2 ( {\text{Mn}}^{ 3 + } + {\text{e}}^{-} \rightarrow {\text{Mn}}^{ 2 + } ) ; & {\text{E}}^{\circ } = + \text{1.51 V} \end{matrix}$ The ${\text{E}}^{\circ }$ for $3 {\text{Mn}}^{ 2 + } \rightarrow \text{Mn} + 2 {\text{Mn}}^{ 3 + }$ will be :

The amount of $\mathrm{BaSO}_4$ formed upon mixing 100 $\mathrm{mL}$ of $20.8 \% \mathrm{BaCl}_2$ solution with $50 \mathrm{~mL}$ of $9.8 \%$ $\mathrm{H}_2 \mathrm{SO}_4$ solution will be: $(\mathrm{Ba}=137, \mathrm{Cl}=35.5, \mathrm{~S}=32, \mathrm{H}=1$ and $\mathrm{O}=16$ )

The de-Broglie wavelength of a particle of mass $6.63 \mathrm{~g}$ moving with a velocity of $100 \mathrm{~ms}^{-1}$ is:

How many electrons would be required to deposit $6.35 \mathrm{~g}$ of copper at the cathode during the electrolysis of an aqueous solution of copper sulphate? (Atomic mass of copper $=63.5 \mathrm{u}, \mathrm{N}_{\mathrm{A}}=$ Avogadro's constant):

The standard electrode potentials $( {\text{E}}_{ {\text{M}}^{+} / \text{M} }^{\text{o}} )$ of four metals $\text{A,} \text{B,} \text{C}$ and $\text{D}$ are $-\text{1}\text{.2} \text{V,}$$\text{0}\text{.6} \text{V}$, $\text{0}\text{.85} \text{V}$ and $-\text{0}\text{.76} \text{V}$, respectively. The sequence of deposition of metals on applying potential is

Consider separate solutions of $0.500M{C}_{2}{H}_{5}\mathrm{OH}(\mathrm{aq}),0.100M{\mathrm{Mg}}_{3}{({\mathrm{PO}}_{4})}_{2}(\mathrm{aq}),0.250M\mathrm{KBr}(\mathrm{aq})$ and $0.125M{\mathrm{Na}}_{3}{\mathrm{PO}}_{4}(\mathrm{aq})$ at $25^{\circ}C$. Which statement is true about these solutions, assuming all salts to be strong electrolytes?

For the reaction, $2 \mathrm{~N}_2 \mathrm{O}_5 \rightarrow 4 \mathrm{NO}_2+\mathrm{O}_2$, the rate equation can be expressed in two ways $-\frac{\mathrm{d}\left[\mathrm{N}_2 \mathrm{O}_5\right]}{\mathrm{dt}}=\mathrm{k}\left[\mathrm{N}_2 \mathrm{O}_5 \quad\right] n \mathrm{nd}$ $+\frac{\mathrm{d}\left[\mathrm{NO}_2\right]}{\mathrm{dt}}=\mathrm{k}^{\prime}\left[\mathrm{N}_2 \mathrm{O}_5\right]$ $\mathrm{k}$ and $\mathrm{k}^{\prime}$ are related as:

Zirconium phosphate $[{\mathrm{Zr}}_{3}{({\mathrm{PO}}_{4})}_{4}]$ dissociates into three zirconium cations of charge $+4$ and four phosphate anions of charge $-3$. If molar solubility of zirconium phosphate is denoted by $s$ and its solubility product by ${K}_{\mathrm{sp}}$ then which of the following relationship between $s$ and ${K}_{\mathrm{sp}}$ is correct ?

Excited hydrogen atom emits light in the ultraviolet region at $2.47 \times 10^{15} \mathrm{~Hz}$. With this frequency, the energy of a single photon is: $\left(\mathrm{h}=6.63 \times 10^{-34} \mathrm{Js}\right)$

Choose the correct statement with respect to the vapour pressure of a liquid among the following :

The conjugate base of hydrazoic acid is:

For the reaction ${ \text{SO}}_{2} (\text{g})+\frac{1}{2} {\text{O}}_{2} (\text{g})\rightleftharpoons { \text{SO}}_{3} (\text{g})$ , if ${\text{K}}_{\text{P}} = {\text{K}}_{\text{C}} { ( \text{RT} ) }^{x}$ where the symbols have usual meaning then the value of $x$ is: (assuming ideality)

The molar heat capacity $\left(\mathrm{C}_{\mathrm{p}}\right)$ of $\mathrm{CD}_2 \mathrm{O}$ is 10 cals at $1000 \mathrm{~K}$. The change in entropy associated with cooling of $32 \mathrm{~g}$ of $\mathrm{CD}_2 \mathrm{O}$ vapour from $1000 \mathrm{~K}$ to $100 \mathrm{~K}$ at constant pressure will be: $(\mathrm{D}=$ deuterium, atomic mass $=2 \mathrm{u})$

At a certain temperature, only 50% HI is dissociated into H$_{2}$ and I$_{2}$ at equilibrium. The equilibrium constant is :

A gaseous compound of nitrogen and hydrogen contains $12.5 \%$ (by mass) of hydrogen. The density of the compound relative to hydrogen is 16. The molecular formula of the compound is:

Consider the reaction : ${\text{H}}_{2} {\text{SO}}_{ 3 ( \text{aq} ) } + {\text{Sn}}_{( \text{aq} )}^{ 4 + } + {\text{H}}_{2} {\text{O}}_{( l⁡ )} \rightarrow {\text{Sn}}_{( \text{aq} )}^{ 2 + } + {\text{HSO}}_{ 4 ( \text{aq} ) }^{-} + 3 {\text{H}}_{( \text{aq} )}^{+}$ Which of the following statements is correct ?

The observed osmotic pressure for a $0.10M$ solution of $\mathrm{Fe}({\mathrm{NH}}_{4}{)}_{2}({\mathrm{SO}}_{4}{)}_{2}$ at $25^{\circ}C$ is $10.8\mathrm{atm}$. The expected and experimental (observed) values of Van't Hoff factor '$i$' will be respectively; $(R=0.082L\mathrm{atm}{k}^{-}{\mathrm{mol}}^{-1})$

The equivalent conductance of $\mathrm{NaCl}$ at concentration C and at infinite dilution are ${\lambda }_{\text{C}}$ and ${\lambda }_{\infty }$, respectively. The correct relationship between ${\lambda }_{\text{C}}$ and ${\lambda }_{\infty }$ is given as : (where the constant B is positive)

If $\lambda_0$ and $\lambda$ be threshold wavelength and wavelength of incident light, the velocity of photoelectron ejected from the metal surface is:

A current of $10.0A$ flows for $2.00h$ through an electrolytic cell containing a molten salt of metal $X$. This results in the decomposition of $0.250\mathrm{mol}$ of metal $X$ at the cathode. The oxidation state of $X$ in the molten salt is: $(F=96,500C)$

In some solutions, the concentration of $\mathrm{H}_3 \mathrm{O}^{+}$ remains constant even when small amounts of strong acid or strong base are added to them. These solutions are known as:

How many electrons are involved in the following redox reaction ? ${\text{Cr}}_{2} {\text{O}}_{7}^{ 2 - } + {\text{Fe}}^{ 2 + } + {\text{C}}_{2} {\text{O}}_{4}^{ 2 - } \rightarrow {\text{Cr}}^{3 +} + {\text{Fe}}^{ 3 + } + {\text{CO}}_{2}$ (Unbalanced)

The standard enthalpy of formation $\left(\Delta_f \mathrm{H}^{\circ}{ }_{298}\right)$ for methane, $\mathrm{CH}_4$ is $-74.9 \mathrm{~kJ} \mathrm{~mol}^{-1}$. In order to calculate the average energy given out in the formation of a $\mathrm{C}-\mathrm{H}$ bond from this it is necessary to know which one of the following?