JEE Main Chemistry — Physical Chemistry previous year questions with solutions.
At $310K$, the solubility of ${\mathrm{CaF}}_{2}$ in water is $2.34\times {10}^{-3}g/100\mathrm{mL}$. The solubility product of ${\mathrm{CaF}}_{2}$ is ---- $\times {10}^{-8}{(\mathrm{mol}/L)}^{3}$(nearest integer). (Given molar mass : ${\mathrm{CaF}}_{2}=78g{\mathrm{mol}}^{-1}$)
The ${K}_{\mathrm{sp}}$ for bismuth sulphide $({\mathrm{Bi}}_{2}{S}_{3})$ is $1.08\times {10}^{-73}$. The solubility of ${\mathrm{Bi}}_{2}{S}_{3}$ in ${\mathrm{molL}}^{-1}$ at $298K$ is
The half life for the decomposition of gaseous compound $A$ is $240s$ when the gaseous pressure was $500$ Torr initially. When the pressure was $250$ Torr, the half life was found to be $4.0\mathrm{min}$. The order of the reaction is _____ (Nearest integer)
In base vs. Acid titration, at the end point methyl orange is present as
If ${O}_{2}$ gas is bubbled through water at $303K$, the number of millimoles of ${O}_{2}$ gas that dissolve in $1$ litre of water is____(Nearest integer) (Given : Henry's Law constant for ${O}_{2}$ at $303K$ is $46.82k$ bar and partial pressure of ${O}_{2}=0.920$ bar) (Assume solubility of ${O}_{2}$ in water is too small, nearly negligible)
A solution of ${\mathrm{Fe}}_{2}{({\mathrm{SO}}_{4})}_{3}$ is electrolyzed for '$x$' min with a current of $1.5A$ to deposit $0.3482g$ of $\mathrm{Fe}$. The value of $x$ is - [nearest integer] Given : $1F=96500{\mathrm{Cmol}}^{-1}$. Atomic mass of $\mathrm{Fe}=56{\mathrm{gmol}}^{-1}$
At $25^{\circ}C$ and $1$ atm pressure, the enthalpies of combustion are as given below: <table class="pyq-table"><tbody><tr><td>Substance</td><td>${H}_{2}$</td><td>$C$ (graphite)</td><td>${C}_{2}{H}_{6}(g)$</td></tr><tr><td>$\frac{{\Delta }_{c}{H}^{\Theta }}{{\mathrm{kJmol}}^{-1}}$</td><td>$-286.0$</td><td>$-394.0$</td><td>$-1560.0$</td></tr></tbody></table>The enthalpy of formation of ethane is
Assuming $1\mu g$ of trace radioactive element $X$ with a half life of $30$ years is absorbed by a growing tree. The amount of $X$ remaining in the tree after $100$ years is_____$\times {10}^{-1}\mu g$. [Given : $\mathrm{ln}10=2.303;\mathrm{log}2=0.30$]
$\begin{matrix}[A] & \rightarrow & [B] \\ \mathrm{Reactant} & & \mathrm{Product}\end{matrix}$ If formation of compound $[B]$ follows the first order of kinetics and after $70$ minutes the concentration of $[A]$ was found to be half of its initial concentration. Then the rate constant of the reaction is $x\times {10}^{-6}{s}^{-1}$. The value of $x$ is____
It has been found that for a chemical reaction with rise in temperature by $9K$ the rate constant gets doubled. Assuming a reaction to be occurring at $300K$, the value of activation energy is found to be ${\mathrm{kJmol}}^{-1}$. [nearest integer] (Given $\mathrm{ln}10=2.3,R=8.3J{K}^{-1}{\mathrm{mol}}^{-1},\mathrm{log}2=0.30$)
Given below are two statements : one is labelled as Assertion and the other is labelled as Reason. Assertion: At $10^{\circ}C$, the density of a $5M$ solution of $\mathrm{KCl}$ [atomic masses of $K&\mathrm{Cl}$ are $39&35.5g{\mathrm{mol}}^{-1}$ respectively], is '$x$' ${\mathrm{gml}}^{-1}$. The solution is cooled to $-21^{\circ}C$. The molality of the solution will remain unchanged. Reason: The molality of a solution does not change with temperature as mass remains unaffected with temperature. In the light of the above statements, choose the correct answer from the options given below.
Given below are two statements: Statement I: For $\mathrm{KI}$, molar conductivity increases steeply with dilution. Statement II: For carbonic acid, molar conductivity increases slowly with dilution. In the light of the above statements, choose the correct answer from the options given below
If a rocket runs on a fuel $({C}_{15}{H}_{30})$ and liquid oxygen, the weight of oxygen required and ${\mathrm{CO}}_{2}$ released for every litre of fuel respectively are : (Given : density of the fuel is $0.756g/\mathrm{mL}$)
The enthalpy of combustion of propane, graphite and dihydrogen at $298K$ are: $-2220.0\mathrm{kJ}{\mathrm{mol}}^{-1}$, $-393.5\mathrm{kJ}{\mathrm{mol}}^{-1}$ and $-285.8\mathrm{kJ}{\mathrm{mol}}^{-1}$ respectively. The magnitude enthalpy of formation of propane $({C}_{3}{H}_{8})$ is _____ ${\mathrm{kJmol}}^{-1}$. (Nearest integer)
${\mathrm{PCl}}_{5}$ dissociates as ${\mathrm{PCl}}_{5}(g)\rightleftharpoons {\mathrm{PCl}}_{3}(g)+{\mathrm{Cl}}_{2}(g)$ $5$ moles of ${\mathrm{PCl}}_{5}$ are placed in a $200$ litre vessel which contains $2$ moles of ${N}_{2}$ and is maintained at $600K$. The equilibrium pressure is $2.46\mathrm{atm}$. The equilibrium constant ${K}_{p}$ for the dissociation of ${\mathrm{PCl}}_{5}$ is___$\times {10}^{-3}$. (nearest integer) (Given: $R=0.082L$ atm ${K}^{-1}{\mathrm{mol}}^{-1}$; Assume ideal gas behaviour)
For the given first order reaction $A\rightarrow B$ the half life of the reaction is $0.3010\mathrm{min}$. The ratio of the initial concentration of reactant to the concentration of reactant at time $2.0\mathrm{min}$ will be equal to _____. (Nearest integer)
$40%$ of $\mathrm{HI}$ undergoes decomposition to ${H}_{2}$ and ${I}_{2}$ at $300K.{\Delta G}^{\Theta }$ for this decompostion reaction at one atmopsphere pressure is____${\mathrm{Jmol}}^{-1}$-[nearest integer] $(\mathrm{Use}R=8.31{\mathrm{JK}}^{-1}{\mathrm{mol}}^{-1};\mathrm{log}2=0.3010,\mathrm{ln}10=2.3,\mathrm{log}3=0.477)$
Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$ Assertion $A$ : The reduction of a metal oxide is easier if the metal formed is in liquid state than solid state. Reason $R$ : The value of ${\Delta G}^{\Theta }$ becomes more on negative side as entropy is higher in liquid state than solid state. In the light of the above statements. Choose the most appropriate answer from the options given below
Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$. Assertion $A$ :Phenolphthalein is a $\mathrm{pH}$ dependent indicator, remains colourless in acidic solution and gives pink colour in basic medium Reason $R$ : Phenolphthalein is a weak acid. It doesn't dissociate in basic medium. In the light of the above statements, choose the most appropriate answer from the options given below
Which of the following statements are correct? (A) The electronic configuration of $\mathrm{Cr}$ is $[\mathrm{Ar}]3{d}^{5}4{s}^{1}$. (B) The magnetic quantum number may have a negative value. (C) In the ground state of an atom, the orbitals are filled in order of their increasing energy order. (D) The total number of nodes are given by $n-2$. Choose the most appropriate answer from the options given below.
Given below are two statements. One is labelled as Assertion $A$ and the other is labelled as Reason $R$. Assertion $A$ : Energy of $2s$ orbital of hydrogen atom is greater than that of $2s$ orbital of lithium. Reason $R$ : Energies of the orbitals in the same subshell decrease with increase in the atomic number. In the light of the above statements, choose the correct answer from the options given below.
Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$ Assertion $A$ : Permanganate titration are not performed in presence of hydrochloric acid. Reason $R$ : Chlorine is formed as a consequence of oxidation of hydrochloric acid. In the light of the above statements, choose the correct answer from the options given below
The resistance of a conductivity cell containing $0.01\mathrm{MKCl}$ solution at $298K$ is $1750\Omega$. If the conductivity of $0.01\mathrm{MKCl}$ solution at $298K$ is $0.152\times {10}^{-3}S{\mathrm{cm}}^{-1}$, then the cell constant of the conductivity cell is____$\times {10}^{-3}{\mathrm{cm}}^{-1}$
Elevation in boiling point for $1.5$ molal solution of glucose in water is $4K$. The depression in freezing point for $4.5$ molal solution of glucose in water is $4K$. The ratio of molal elevation constant to molal depression constant $({K}_{b}/{K}_{f})$ is