Physical Chemistry PYQ — Page 30

Which of the following options are correct for the reaction? $2{[\mathrm{Au}(\mathrm{CN}{)}_{2}]}^{-}(\mathrm{aq})+\mathrm{Zn}(s)\rightarrow 2\mathrm{Au}(s)+{[\mathrm{Zn}(\mathrm{CN}{)}_{4}]}^{2-}(\mathrm{aq})$ A. Redox reaction B. Displacement reaction C. Decomposition reaction D. Combination reaction Choose the correct answer from the options given below:

In alkaline medium, the reduction of permanganate anion involves a gain of ____________ electrons.

At $298K$, a $1$ litre solution containing $10\mathrm{mmol}$ of ${\mathrm{Cr}}_{2}{O}_{7}^{2-}$ and $100\mathrm{mmol}$ of ${\mathrm{Cr}}^{3+}$ shows a $\mathrm{pH}$ of $3.0$. Given : ${\mathrm{Cr}}_{2}{O}_{7}\rightarrow 2-{\mathrm{Cr}}^{3+};{E}^{0}=1.330V$ and $\frac{2.303\mathrm{RT}}{F}=0.059V$ The potential for the half cell reaction is $x\times {10}^{-3}V$ . The value of $x$ is _____ .

$1g$ of a carbonate $({M}_{2}{\mathrm{CO}}_{3})$ on treatment with excess $\mathrm{HCl}$ produces $0.01\mathrm{mol}$ of ${\mathrm{CO}}_{2}$. The molar mass of ${M}_{2}{\mathrm{CO}}_{3}$ is ${\mathrm{gmol}}^{-1}$. (Nearest integer)

An organic compound undergoes first order decomposition. If the time taken for the $60%$ decomposition is $540s$, then the time required for $90%$ decomposition will be is _____ s. (Nearest integer). Given : $\mathrm{ln}10=2.3;\mathrm{log}2=0.3$

Consider the following pairs of solution which will be isotonic at the same temperature. The number of pairs of solutions is/ are _____ A. $1M\mathrm{aq}.\mathrm{NaCl}$ and $2M\mathrm{aq}.$ urea B. $1M\mathrm{aq}.{\mathrm{CaCl}}_{2}$ and $1.5M\mathrm{aq}.\mathrm{KCl}$ C. $1.5M\mathrm{aq}.{\mathrm{AlCl}}_{3}$ and $2M\mathrm{aq}.{\mathrm{Na}}_{2}{\mathrm{SO}}_{4}$ D. $2.5M\mathrm{aq}.\mathrm{KCl}$ and $1M\mathrm{aq}.{\mathrm{Al}}_{2}({\mathrm{SO}}_{4}{)}_{3}$

$2{\mathrm{IO}}_{3}^{-}+{\mathrm{xI}}^{-}+12{H}^{+}\rightarrow 6{I}_{2}+6{H}_{2}$ What is the value of $x$?

What happens when methane undergoes combustion in systems A and B respectively? 

The number of incorrect statement/s from the following is ______________ A. The successive half lives of zero order reactions decreases with time. B. A substance appearing as reactant in the chemical equation may not affect the rate of reaction C. Order and molecularity of a chemical reaction can be a fractional number D. The rate constant units of zero and second order reaction are $\mathrm{molL}-1{s}^{-1}$ and ${\mathrm{mol}}^{-1}L{s}^{-1}$ respectively

Solution of $12g$ of non-electrolyte (A) prepared by dissolving it in $1000\mathrm{mL}$ of water exerts the same osmotic pressure as that of $0.05M$ glucose solution at the same temperature. The empirical formula of $A$ is ${\mathrm{CH}}_{2}O.$ The molecular mass of $A$ is $________g.$ (Nearest integer)

Incorrect statement for the use of indicator in acid-base titration is:

Strong reducing and oxidizing agents among the following , respectively, are

At $27^{\circ}C$, a solution containing $2.5g$ of solute in $250.0\mathrm{mL}$ of solution exerts an osmotic pressure of $400\mathrm{Pa}$. The molar mass of the solute is g ${\mathrm{mol}}^{-1}$ (Nearest integer) (Given : $R=0.083L$ bar $-1{\mathrm{mol}}^{-1}$ )

Gibbs energy vs $T$ plot for the formation of oxides is given below.  For the given diagram, the correct statement is-

The molality of a $10%(v/V)$ solution of di-bromine solution in ${\mathrm{CCl}}_{4}$ (carbon tetrachloride) is $x$ '. $x=$ $_____\times {10}^{-2}M$. (Nearest integer) [Given : molar mass of ${\mathrm{Br}}_{2}=160g{\mathrm{mol}}^{-1}$ atomic mass of $C=12g{\mathrm{mol}}^{-1}$ atomic mass of $\mathrm{Cl}=35.5g{\mathrm{mol}}^{-1}$ density of dibromine $=3.2g{\mathrm{cm}}^{-3}$ density of ${\mathrm{CCl}}_{4}=1.6g{\mathrm{cm}}^{-3}]$

The standard reduction potentials at $295K$ for the following half cells are given below: <table class="pyq-table"><tbody><tr><td>${{\mathrm{NO}}_{3}}^{-}+4{H}^{+}+3{e}^{-}\rightarrow \mathrm{NO}(g)+2{H}_{2}O$</td><td>${E}^{o}=0.97V$</td></tr><tr><td>${V}^{2+}(\mathrm{aq})+2{e}^{-}\rightarrow V(s)$</td><td>${E}^{o}=-1.19V$</td></tr><tr><td>${\mathrm{Fe}}^{3+}(\mathrm{aq})+3{e}^{-}\rightarrow \mathrm{Fe}(s)$</td><td>${E}^{o}=-0.04V$</td></tr><tr><td>${\mathrm{Ag}}^{+}(\mathrm{aq})+{e}^{-}\rightarrow \mathrm{Ag}(s)$</td><td>${E}^{o}=0.80V$</td></tr><tr><td>${\mathrm{Au}}^{3+}(\mathrm{aq})+3{e}^{-}\rightarrow \mathrm{Au}(s)$</td><td>${E}^{o}=1.40V$</td></tr></tbody></table>The number of metal(s) which will be oxidised by ${{\mathrm{NO}}_{3}}^{-}$ in aqueous solution is _____.

It is observed that characteristic X-ray spectra of elements show regularity. When frequency to the power 'n' i.e. ${v}^{n}$ of X-rays emitted is plotted against atomic number $Z$, the following graph is obtained.  The value of 'n' is

Which one of the following statements is correct for electrolysis of brine solution?

Consider the following reaction that goes from $A$ to $B$ in three steps as shown below:  Choose the correct option <table class="pyq-table"><tbody><tr><td></td><td>Number of Intermediates</td><td>Number of Activated Complexes</td><td>Rate determining step</td></tr><tr><td>$(1)$</td><td>$2$</td><td>$3$</td><td>$I$</td></tr><tr><td>$(2)$</td><td>$2$</td><td>$3$</td><td>$\mathrm{III}$</td></tr><tr><td>$(3)$</td><td>$2$</td><td>$3$</td><td>$\mathrm{II}$</td></tr><tr><td>$(4)$</td><td>$3$</td><td>$2$</td><td>$\mathrm{II}$</td></tr></tbody></table>

If $5$ moles of ${\mathrm{BaCl}}_{2}$ is mixed with $2$ moles of ${\mathrm{Na}}_{3}{\mathrm{PO}}_{4},$ the maximum number of moles of ${\mathrm{Ba}}_{3}{({\mathrm{PO}}_{4})}_{2}$formed is $_________$ (Nearest integer)

The radius of the 2$^{nd}$ orbit of ${\mathrm{Li}}^{2+}$ is $x$. The expected radius of the 3$^{rd}$ orbit of ${\mathrm{Be}}^{3+}$ is

$Pt(s){H}_{2}(g)(1\mathrm{bar})|{H}^{+}(\mathrm{aq})(1M)||{M}^{3+}(\mathrm{aq}),{M}^{+}(\mathrm{aq})|\mathrm{Pt}(s)$ The ${E}_{\text{cell }}$ for the given cell is $0.1115V$ at $298K$ When $\frac{[{M}^{+}(\mathrm{aq})]}{[{M}^{3+}(\mathrm{aq})]}={10}^{a}$ The value of a is ___________ Given : ${E}^{\theta }={M}^{3+}/{M}^{+}0.2V$ $\frac{2.303\mathrm{RT}}{F}=0.059V$

A student has studied the decomposition of a gas $A{B}_{3}$ at $25^{\circ}C$. He obtained the following data <table class="pyq-table"><tbody><tr><td>$p(mmHg)$</td><td>$50$</td><td>$100$</td><td>$200$</td><td>$400$</td></tr><tr><td>Relative ${t}_{\frac{1}{2}}(s)$</td><td>$4$</td><td>$2$</td><td>$1$</td><td>$0.5$</td></tr></tbody></table>The order of the reaction is

The orbital angular momentum of an electron in $3s$ orbital is $\frac{\mathrm{xh}}{2\pi }$. The value of $x$ is (nearest integer)