JEE Main Chemistry — Physical Chemistry previous year questions with solutions.
The de-Broglie's wavelength of electron present in first Bohr orbit of ' $\mathrm{H}$ ' atom is:
The combustion of benzene $(l)$ gives ${\mathrm{CO}}_{2}(g)$ and ${H}_{2}O(l).$ Given that heat of combustion of benzene at constant volume is $-3263.9 \mathrm{kJ} {\mathrm{mol}}^{-1}$ at $25^{\circ}C;$ the heat of combustion $(\mathrm{in} \mathrm{kJ} {\mathrm{mol}}^{-1})$ of benzene at constant pressure will be $(R=8.314 {\mathrm{JK}}^{-1} {\mathrm{mol}}^{-1})$
In which of the following reactions, an increase in the volume of the container will favour the formation of products?
In which of the following reactions, an increase in the volume of the container will favour the formation of products?
If 50 % of a reaction occurs in 100 second and 75 % of the reaction occurs in 200 second, the order of this reaction is:
How long (approximate) should water be electrolysed by passing through $100$$\mathrm{amperes}$current so that the oxygen released can completely burn $27.66g$ of diborane? (Atomic weight of $B=10.8u$)
Given (i) $2 \mathrm{Fe}_2 \mathrm{O}_3(\mathrm{~s}) \rightarrow 4 \mathrm{Fe}(\mathrm{s})+3 \mathrm{O}_2(\mathrm{~g})$; $$ \Delta_{\mathrm{r}} \mathrm{G}^{\circ}=+1487.0 \mathrm{~kJ} \mathrm{~mol}^{-1} $$ (ii) $2 \mathrm{CO}(\mathrm{g})+\mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g})$; $$ \Delta_{\mathrm{r}} \mathrm{G}^{\circ}=-514.4 \mathrm{~kJ} \mathrm{~mol}^{-1} $$ Free energy change, $\Delta_{\mathrm{r}} \mathrm{G}^{\circ}$ for the reaction $2 \mathrm{Fe}_2 \mathrm{O}_3(\mathrm{~s})+6 \mathrm{CO}(\mathrm{g}) \rightarrow 4 \mathrm{Fe}(\mathrm{s})+6 \mathrm{CO}_2(\mathrm{~g})$ will be:
For$1\mathrm{molal}$aqueous solution of the following compounds, which one will show the highest freezing point?
For which of the following reactions, $\Delta H$ is equal to $\Delta U$?
For which of the following reactions, $\Delta \mathrm{H}$ is equal to $\Delta \mathrm{U}$ ?
For which of the following processes, $\Delta S$ is negative?
For standardizing $\mathrm{NaOH}$ solution, which of the following is used as a primary standard?
For per gram of reactant, the maximum quantity of $\mathrm{N}_2$ gas is produced in which of the following thermal decomposition reactions? (Given: Atomic wt. : $\mathrm{Cr}=52 \mathrm{u}, \mathrm{Ba}=137 \mathrm{u}$ ).
For a first order reaction, $\mathrm{A} \rightarrow \mathrm{P}, \mathrm{t}_{1 / 2}$ (half-life) is 10 days. The time required for $\frac{1}{4}^{\text {th }}$ conversion of $\mathrm{A}$ (in days) is: $(\ln 2=0.693, \ln 3=1.1)$.
Following four solutions are prepared by mixing different volumes of $\mathrm{NaOH}$ and $\mathrm{HCl}$ of different concentrations, $\mathrm{pH}$ of which one of them will be equal to 1 ?
Ejection of the photoelectron from metal in the photoelectric effect experiment can be stopped by applying $0.5V$, when the radiation of $250\mathrm{nm}$ is used. The work function of the metal is
Ejection of the photoelectron from metal in the photoelectric effect experiment can be stopped by applying $0.5 \mathrm{~V}$ when the radiation of $250 \mathrm{~nm}$ is used. The work function of the metal is :
${N}_{2}{O}_{5}$ decomposes to ${\mathrm{NO}}_{2}$ and ${O}_{2}$ follows the first order kinetics. After $50$ minutes, the pressure inside the vessel increases from $50\mathrm{mm}\mathrm{Hg}$ to $87.5\mathrm{mm}\mathrm{Hg}$. The pressure of the gaseous mixture after $100$ minutes at constant temperature will be:
$\mathrm{N}_2 \mathrm{O}_5$ decomposes to $\mathrm{NO}_2$ and $\mathrm{O}_2$ and follows first order kinetics. After $50$ minutes, the pressure inside the vessel increases from $50 \mathrm{~mm} \mathrm{~Hg}$ to $87.5 \mathrm{~mm} \mathrm{~Hg}$. The pressure of the gaseous mixture after $100$ minutes at constant temperature will be ______.
At ${518}^{o}C,$ the rate of decomposition of a sample of gaseous acetaldehyde, initially at a pressure of $363 \mathrm{Torr}$ was $1.00 \mathrm{Torr} {s}^{-1}$ when $5%$ had reacted and $0.50 \mathrm{Torr} {s}^{-1}$ when 33% had reacted. The order of the reaction is:
$\Delta_{\mathrm{f}} \mathrm{G}^{\circ}$ at $500 \mathrm{~K}$ for substance ' $\mathrm{S}$ ' in liquid state and gaseous state are $+100.7 \mathrm{kcal} \mathrm{mol}^{-1}$ and $+103$ $\mathrm{kcal} \mathrm{mol}^{-1}$, respectively. Vapour pressure of liquid ' $\mathrm{S}$ ' at $500 \mathrm{~K}$ is approximately equal to: $$ \left(\mathrm{R}=2 \mathrm{cal} \mathrm{K}^{-1} \mathrm{~mol}^{-1}\right) \text {. } $$
At a certain temperature in a 5L vessel, 2 moles of carbon monoxide and 3 moles of chlorine were allowed to reach equilibrium according to the reaction, $\mathrm{CO}+\mathrm{Cl}_2 \rightleftharpoons \mathrm{COCl}_2$. At equilibrium, if one mole of $\mathrm{CO}$ is present then equilibrium constant $\left(K_{\mathrm{c}}\right)$ for the reaction is:
At 320 K, a gas ${A}_{2}$ is 20 % dissociated to $A(g)$ . The standard Gibbs free energy change at $320 K and 1 atm in J mo{l}^{–1}$ is approximately: $(R = 8.314 {\mathrm{JK}}^{–1} {\mathrm{mol}}^{–1} ;\mathrm{ln}2 = 0.693 ;\mathrm{ln}3 = 1.098)$
An unknown chlorohydrocarbon has 3.55 % of chlorine. If each molecule of the hydrocarbon has one chlorine atom only; chlorine atoms present in 1 g of chlorohydrocarbon are :(Atomic wt. of $\mathrm{Cl}=35.5 u;$ Avogadro constant $=6.023\times {10}^{23} {\mathrm{mol}}^{–1}$)