Physical Chemistry PYQ — Page 20

Time required for completion of $99.9%$ of first order reaction is ________ times of half life $({t}_{1/2})$ of the reaction

The mass of silver (Molar mass of $\mathrm{Ag}:108{\mathrm{gmol}}^{-1}$ ) displaced by a quantity of electricity which displaces $5600\mathrm{mL}$ of ${O}_{2}$ at S.T.P. will be _____ g.

Which of the following reactions are disproportionation reactions? $(1){\mathrm{Cu}}^{+}\rightarrow {\mathrm{Cu}}^{2+}+\mathrm{Cu}$ $(2) 3{\mathrm{MnO}}_{4}^{2-}+4{H}^{+}\rightarrow 2{\mathrm{MnO}}_{4}^{-}+{\mathrm{MnO}}_{2}+2{H}_{2}O$ $(3)2{\mathrm{KMnO}}_{4}\rightarrow {K}_{2}{\mathrm{MnO}}_{4}+{\mathrm{MnO}}_{2}+{O}_{2}$ $(4)2{\mathrm{MnO}}_{4}^{-}+3{\mathrm{Mn}}^{2+}+2{H}_{2}O\rightarrow 5{\mathrm{MnO}}_{2}+4{H}^{+}$ Choose the correct answer from the options given below:

A constant current was passed through a solution of ${\mathrm{AuCl}}_{4}^{-}$ ion between gold electrodes. After a period of $10.0$ minutes, the increase in mass of cathode was $1.314g$. The total charge passed through the solution is ___$\times {10}^{-2}F$. (Given atomic mass of $\mathrm{Au}=197)$

The following data were obtained during the first order thermal decomposition of a gas $A$ at constant volume: $A(g)\rightarrow 2B(g)+C(g)$ S. No Time/s Total pressure/(atm) $1.$ $0$ $0.1$ $2.$ $115$ $0.28$ The rate constant of the reaction is _______ $\times {10}^{-2}{s}^{-1}$ (nearest integer)

If $50\mathrm{mL}$ of $0.5M$ oxalic acid is required to neutralise $25\mathrm{mL}$ of $\mathrm{NaOH}$ solution, the amount of $\mathrm{NaOH}$ in $50\mathrm{mL}$ of given $\mathrm{NaOH}$ solution is_______g.

${A}_{(g)}\rightleftharpoons {B}_{(g)}+\frac{C}{{2}^{(g)}}$. The correct relationship between ${K}_{P},\alpha$ and equilibrium pressure $P$ is

Three moles of an ideal gas are compressed isothermally from \(60 \mathrm{~L}\) to \(20 \mathrm{~L}\) using constant pressure of \(5 \mathrm{~atm}\). Heat exchange \(\mathrm{Q}\) for the compression is - ______ Lit. atm.

${K}_{a}$ for ${\mathrm{CH}}_{3}\mathrm{COOH}$ is $1.8\times {10}^{-5}$ and ${K}_{b}$ for ${\mathrm{NH}}_{4}\mathrm{OH}$ is $1.8\times {10}^{-5}.$ The $\mathrm{pH}$ of ammonium acetate solution will be

The molarity of $1L$ orthophosphoric acid $({H}_{3}{\mathrm{PO}}_{4})$ having $70%$ purity by weight (specific gravity $1.54g{\mathrm{cm}}^{-3}$) is ______ $M$. (Molar mass of ${H}_{3}{\mathrm{PO}}_{4}=98g{\mathrm{mol}}^{-1}$)

The following reaction occurs in the Blast furnance where iron ore is reduced to iron metal \(\mathrm{Fe}_2 \mathrm{O}_{3(\mathrm{~s})}+3 \mathrm{CO}_{(\mathrm{g})} \rightleftharpoons \mathrm{Fe}_{(\mathrm{l})}+3 \mathrm{CO}_{2(\mathrm{~g})}\) Using the Le-chatelier's principle, predict which one of the following will not disturb the equilibrium.

Consider the following data for the given reaction $2{\mathrm{HI}}_{(g)}\rightarrow {H}_{2(g)}+{I}_{2(g)}$ $\begin{matrix}\mathrm{HI}({\mathrm{molL}}^{-1}) & 0.005 & 0.01 & 0.02\end{matrix}$ Rate $({\mathrm{molL}}^{-1}{s}^{-1})7.5\times {10}^{-4}3.0\times {10}^{-3}1.2\times {10}^{-2}$ The order of the reaction is __________.

Among the following halogens \(\mathrm{F}_2, \mathrm{Cl}_2, \mathrm{Br}_2\) and \(\mathrm{I}_2\) Which can undergo disproportionation reactions?

Given below are two statements : Statement (I) : Potassium hydrogen phthalate is a primary standard for standardisation of sodium hydroxide solution. Statement (II) : In this titration phenolphthalein can be used as indicator. In the light of the above statements, choose the most appropriate answer from the options given below:

In acidic medium, ${K}_{2}{\mathrm{Cr}}_{2}{O}_{7}$ shows oxidising action as represented in the half reaction ${\mathrm{Cr}}_{2}{O}_{7}^{2-}+{\mathrm{XH}}^{+}+{\mathrm{Ye}}^{-}\rightarrow 2A+{\mathrm{ZH}}_{2}O$ $X,Y,Z$ and $A$ are respectively are:

Consider the following reaction at $298K$. $\frac{3}{2}{O}_{2(g)}\rightleftharpoons {O}_{3(g)}.{K}_{p}=2.47\times {10}^{-29}$ ${\Delta }_{r}{G}^{0}$ for the reaction is _________ $\mathrm{kJ}$. (Given $R=8.314{\mathrm{JK}}^{–1}{\mathrm{mol}}^{–1}$) Round off your answer to the nearest integer.

Integrated rate law equation for a first order gas phase reaction is given by (where ${P}_{i}$ is initial pressure and ${P}_{t}$ is total pressure at time $t$)

Consider the following transformation involving first order elementary reaction in each step at constant temperature as shown below. \(A+B \underset{\text { Step 3 }}{\text { Step } 1} C \xrightarrow{\text { Step 2 }} P\) Some details of the above reactions are listed below. \(\begin{array}{ccc} \text { Step } & \text { Rate constant }\left(\mathbf{s e c}^{-\mathbf{1}}\right) & \text { Activation energy }\left(\mathbf{k J ~ m o l}^{-\mathbf{1}}\right) \\ 1 & \mathrm{k}_1 & 300 \\ 2 & \mathrm{k}_2 & 200 \\ 3 & \mathrm{k}_3 & \mathrm{Ea}_3 \end{array}\) If the overall rate constant of the above transformation \((k)\) is given as \(k=\frac{k_1 k_2}{k_3}\) and the overall activation energy \(\left(\mathrm{E}_{\mathrm{a}}\right)\) is \(400 \mathrm{~kJ} \mathrm{~mol}^{-1}\), then the value of \(\mathrm{Ea}_3\) is \(\qquad\) \(\mathrm{kJ} \mathrm{mol}^{-1}\) (nearest integer)

The half-life of radioisotopic bromine - $82$ is $36$ hours. The fraction which remains after one day is _________$\times {10}^{-2}$. (Given antilog $0.2006=1.587)$ Round off to the nearest integer

The incorrect postulates of the Dalton's atomic theory are : (A) Atoms of different elements differ in mass. (B) Matter consists of divisible atoms. (C) Compounds are formed when atoms of different element combine in a fixed ratio. (D) All the atoms of given element have different properties including mass. (E) Chemical reactions involve reorganisation of atoms. Choose the correct answer from the options given below :

Molality of $0.8M{H}_{2}{\mathrm{SO}}_{4}$ solution (density $1.06g{\mathrm{cm}}^{-3}$ ) is _______$\times {10}^{-3}m$. Round off your answer to the nearest integer.

The osmotic pressure of a dilute solution is $7\times {10}^{5}\mathrm{Pa}$ at $273K$. Osmotic pressure of the same solution at $283K$ is $_______\times {10}^{4}{\mathrm{Nm}}^{-2}$.(Nearest integer)

Mass of methane required to produce $22g$ of $\mathrm{CO}$ after complete combustion is g. (Given Molar mass in g mol$^{-1}$, $C=12.0$, $H=1.0$, $O=16.0)$

If three moles of an ideal gas at $300K$ expand isothermally from $30{\mathrm{dm}}^{3}$ to $45{\mathrm{dm}}^{3}$ against a constant opposing pressure of $80\mathrm{kPa}$, then the amount of heat transferred is __________J.