Chemical Equilibrium

56 Questions Numerical Start JEE Mains Test
2026 Q1 JEE Mains Numerical
14 Mar 2026

$ \mathrm{X}_2(\mathrm{~g})+\mathrm{Y}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{Z}(\mathrm{~g}) $

$\mathrm{X}_2(\mathrm{~g})$ and $\mathrm{Y}_2(\mathrm{~g})$ are added to a 1 L flask and it is found that the system attains the above equilibrium at $\mathrm{T}(\mathrm{K})$ with the number of moles of $\mathrm{X}_2(\mathrm{~g}), \mathrm{Y}_2(\mathrm{~g})$ and $\mathrm{Z}(\mathrm{g})$ being 3,3 and 9 mol respectively (equilibrium moles). Under this condition of equilibrium, 10 mol of $\mathrm{Z}(\mathrm{g})$ is added to the flask and the temperature is maintained at $\mathrm{T}(\mathrm{K})$. Then the number of moles of $\mathrm{Z}(\mathrm{g})$ in the flask when the new equilibrium is established is $\_\_\_\_$ . (Nearest integer)

2026 Q2 JEE Mains Numerical
14 Mar 2026

For the following gas phase equilibrium reaction at constant temperature,

$ \mathrm{NH}_3(\mathrm{~g}) \rightleftharpoons 1 / 2 \mathrm{~N}_2(\mathrm{~g})+3 / 2 \mathrm{H}_2(\mathrm{~g}) $

if the total pressure is $\sqrt{3} \mathrm{~atm}$ and the pressure equilibrium constant $\left(K_p\right)$ is 9 atm , then the degree of dissociation is given as $\left(x \times 10^{-2}\right)^{-1 / 2}$. The value of $x$ is $\_\_\_\_$ . (nearest integer)

2026 Q3 JEE Mains Numerical
14 Mar 2026

Dissociation of a gas $\mathrm{A}_2$ takes place according to the following chemical reaction. At equilibrium, the total pressure is 1 bar at 300 K .

$ \mathrm{A}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{~A}(\mathrm{~g}) $

The standard Gibbs energy of formation of the involved substances has been provided below:

$ \begin{array}{|c|c|} \hline \text { Substance } & \Delta \mathrm{G}_{\mathrm{f}}^{\circ} / \mathrm{kJ} \mathrm{~mol}^{-1} \\ \hline \hline \mathrm{~A}_2 & -100.00 \\ \hline \mathrm{~A} & -50.832 \\ \hline \end{array} $

The degree of dissociation of $\mathrm{A}_2(\mathrm{~g})$ is given by $\left(x \times 10^{-2}\right)^{1 / 2}$ where $x=$

$\_\_\_\_$ . (Nearest integer).

[ Given : $\mathrm{R}=8 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}, \log 2=0.3010, \log 3=0.48$ ]

Assume degree of dissociation is not negligible.

2026 Q4 JEE Mains Numerical
03 Jul 2026

Solid carbon, CaO and $\mathrm{CaCO}_3$ are mixed and allowed to attain equilibrium at T K .

$ \begin{array}{ll} \mathrm{CaCO}_3(\mathrm{~s}) \rightleftharpoons \mathrm{CaO}(\mathrm{~s})+\mathrm{CO}_2(\mathrm{~g}) & \mathrm{Kp}_1=0.08 \mathrm{~atm} \\ \mathrm{C}(\mathrm{~s})+\mathrm{CO}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{CO}(\mathrm{~g}) & \mathrm{Kp}_2=2 \mathrm{~atm} \end{array} $

The partial pressure of CO is __ $\times 10^{-1} \mathrm{~atm}$

2026 Q5 JEE Mains Numerical
03 Jul 2026

In a closed flask at 600 K , one mole of $\mathrm{X}_2 \mathrm{Y}_4(\mathrm{~g})$ attains equilibrium as given below :

$ \mathrm{X}_2 \mathrm{Y}_4(\mathrm{~g}) \rightleftharpoons 2 \mathrm{XY}_2(\mathrm{~g}) $

At equilibrium, $75 \% \mathrm{X}_2 \mathrm{Y}_4(\mathrm{~g})$ was dissociated and the total pressure is 1 atm . The magnitude of $\Delta_{\mathrm{r}} \mathrm{G}^{\ominus}$ (in $\mathrm{kJ} \mathrm{mol}^{-1}$ ) at this temperature is $\_\_\_\_$ . (Nearest Integer)

(Given : $\mathrm{R}=8.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1} ; \ln 10=2.3, \log 2=0.3, \log 3=0.48, \log 5=0.69, \log 7=0.84$ )

2026 Q6 JEE Mains Numerical
03 Jul 2026

The values of pressure equilibrium constant recorded at different temperatures for the following equilibrium reaction have been given below $\mathrm{A}(\mathrm{g}) \rightleftharpoons \mathrm{B}(\mathrm{g})+\mathrm{C}(\mathrm{g})$

$ \begin{array}{|c|c|} \hline \frac{1}{\mathrm{~T}}\left(\mathrm{~K}^{-1}\right) & \log _{10} \mathrm{~K}_{\mathrm{p}} \\ \hline 0.05 & 3.5 \\ \hline 0.06 & 2.5 \\ \hline 0.07 & 1.5 \\ \hline \end{array} $

The magnitude of $\frac{\Delta \mathrm{H}^{\circ}}{\mathrm{R}}$ calculated from the above data is $\_\_\_\_$ . (Nearest integer)

2026 Q7 JEE Mains Numerical
03 Jul 2026

For the following reaction at $50^{\circ} \mathrm{C}$ and at 2 atm pressure,

$ 2 \mathrm{~N}_2 \mathrm{O}_5(\mathrm{~g}) \rightleftharpoons 2 \mathrm{~N}_2 \mathrm{O}_4(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) $

$\mathrm{N}_2 \mathrm{O}_5$ is $50 \%$ dissociated.

The magnitude of standard free energy change at this temperature is $x$.

$x=$ $\_\_\_\_$ $\mathrm{J} \mathrm{mol}^{-1}$ [Nearest integer].

Given : $\mathrm{R}=8.314 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}, \log 2=0.30, \log 3=0.48, \ln 10=2.303$, ${ }^{\circ} \mathrm{C}+273=\mathrm{K}$

2025 Q8 JEE Mains Numerical
14 Mar 2026

The equilibrium constant for decomposition of $\text{H}_2\text{O(g)}$

$ \text{H}_2\text{O(g)} \rightleftharpoons \text{H}_2\text{(g)} + \frac{1}{2}\text{O}_2\text{(g)} \quad (\Delta G^\circ = 92.34 \, \text{kJ mol}^{-1}) $

is $8.0 \times 10^{-3}$ at 2300 K and total pressure at equilibrium is 1 bar. Under this condition, the degree of dissociation ($\alpha$) of water is _________ $\times 10^{-2}$ (nearest integer value).

[Assume $\alpha$ is negligible with respect to 1]

2025 Q9 JEE Mains Numerical
14 Mar 2026

Consider the following equilibrium,

$\mathrm{CO}(\mathrm{~g})+2 \mathrm{H}_2(\mathrm{~g}) \rightleftharpoons \mathrm{CH}_3 \mathrm{OH}(\mathrm{~g})$

0.1 mol of CO along with a catalyst is present in a $2 \mathrm{dm}^3$ flask maintained at 500 K . Hydrogen is introduced into the flask until the pressure is 5 bar and 0.04 mol of $\mathrm{CH}_3 \mathrm{OH}$ is formed. The $K_p^\theta$ is __________ $\times 10^{-3}$ (nearest integer).

Given : $\mathrm{R}=0.08 \mathrm{~dm}^3$ bar $\mathrm{K}^{-1} \mathrm{~mol}^{-1}$

Assume only methanol is formed as the product and the system follows ideal gas behaviour.

2025 Q10 JEE Mains Numerical
14 Mar 2026

$37.8 \mathrm{~g} \mathrm{~N}_2 \mathrm{O}_5$ was taken in a 1 L reaction vessel and allowed to undergo the following reaction at 500 K

$2 \mathrm{~N}_2 \mathrm{O}_{5(\mathrm{~g})} \rightleftharpoons 2 \mathrm{~N}_2 \mathrm{O}_{4(\mathrm{~g})}+\mathrm{O}_{2(\mathrm{~g})}$

The total pressure at equilibrium was found to be 18.65 bar.

Then, $\mathrm{Kp}=$ _________ $\times 10^{-2}$ [nearest integer]

Assume $\mathrm{N}_2 \mathrm{O}_5$ to behave ideally under these conditions.

Given: $\mathrm{R}=0.082$ bar $\mathrm{L} \mathrm{mol}^{-1} \mathrm{~K}^{-1}$

2024 Q11 JEE Mains Numerical
14 Mar 2026

The following concentrations were observed at $500 \mathrm{~K}$ for the formation of $\mathrm{NH}_3$ from $\mathrm{N}_2$ and $\mathrm{H}_2$. At equilibrium ; $\left[\mathrm{N}_2\right]=2 \times 10^{-2} \mathrm{M},\left[\mathrm{H}_2\right]=3 \times 10^{-2} \mathrm{M}$ and $\left[\mathrm{NH}_3\right]=1.5 \times 10^{-2} \mathrm{M}$. Equilibrium constant for the reaction is ________.

2024 Q12 JEE Mains Numerical
14 Mar 2026

For the reaction $\mathrm{N}_2 \mathrm{O}_{4(\mathrm{~g})} \rightleftarrows 2 \mathrm{NO}_{2(\mathrm{~g})}, \mathrm{K}_{\mathrm{p}}=0.492 \mathrm{~atm}$ at $300 \mathrm{~K} . \mathrm{K}_{\mathrm{c}}$ for the reaction at same temperature is _________ $\times 10^{-2}$.

(Given : $\mathrm{R}=0.082 \mathrm{~L} \mathrm{~atm} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$)

2023 Q13 JEE Mains Numerical
14 Mar 2026

4.5 moles each of hydrogen and iodine is heated in a sealed ten litre vessel. At equilibrium, 3 moles of $\mathrm{HI}$ were found. The equilibrium constant for $\mathrm{H}_{2}(\mathrm{~g})+\mathrm{I}_{2}(\mathrm{~g}) \rightleftharpoons 2 \mathrm{HI}(\mathrm{g})$ is _________.

2023 Q14 JEE Mains Numerical
14 Mar 2026

A mixture of 1 mole of $\mathrm{H}_{2} \mathrm{O}$ and 1 mole of $\mathrm{CO}$ is taken in a 10 litre container and heated to $725 \mathrm{~K}$. At equilibrium $40 \%$ of water by mass reacts with carbon monoxide according to the equation :

$\mathrm{CO}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g}) \rightleftharpoons \mathrm{CO}_{2}(\mathrm{~g})+\mathrm{H}_{2}(\mathrm{~g})$.

The equilibrium constant $\mathrm{K}_{\mathrm{c}} \times 10^{2}$ for the reaction is ____________. (Nearest integer)

2023 Q15 JEE Mains Numerical
14 Mar 2026

$\mathrm{A}(g) \rightleftharpoons 2 \mathrm{~B}(g)+\mathrm{C}(g)$

For the given reaction, if the initial pressure is $450 \mathrm{~mm} ~\mathrm{Hg}$ and the pressure at time $\mathrm{t}$ is $720 \mathrm{~mm} ~\mathrm{Hg}$ at a constant temperature $\mathrm{T}$ and constant volume $\mathrm{V}$. The fraction of $\mathrm{A}(\mathrm{g})$ decomposed under these conditions is $x \times 10^{-1}$. The value of $x$ is ___________ (nearest integer)

2023 Q16 JEE Mains Numerical
14 Mar 2026

The number of correct statement/s involving equilibria in physical processes from the following is ________

(A) Equilibrium is possible only in a closed system at a given temperature.

(B) Both the opposing processes occur at the same rate.

(C) When equilibrium is attained at a given temperature, the value of all its parameters became equal.

(D) For dissolution of solids in liquids, the solubility is constant at a given temperature.

2023 Q17 JEE Mains Numerical
14 Mar 2026

The equilibrium composition for the reaction $\mathrm{PCl}_{3}+\mathrm{Cl}_{2} \rightleftharpoons \mathrm{PCl}_{5}$ at $298 \mathrm{~K}$ is given below:

$\left[\mathrm{PCl}_{3}\right]_{\mathrm{eq}}=0.2 \mathrm{~mol} \mathrm{~L}^{-1},\left[\mathrm{Cl}_{2}\right]_{\mathrm{eq}}=0.1 \mathrm{~mol} \mathrm{~L}^{-1},\left[\mathrm{PCl}_{5}\right]_{\mathrm{eq}}=0.40 \mathrm{~mol} \mathrm{~L}^{-1}$

If $0.2 \mathrm{~mol}$ of $\mathrm{Cl}_{2}$ is added at the same temperature, the equilibrium concentrations of $\mathrm{PCl}_{5}$ is __________ $\times 10^{-2} \mathrm{~mol} \mathrm{~L}^{-1}$

Given : $\mathrm{K}_{\mathrm{c}}$ for the reaction at $298 \mathrm{~K}$ is 20

2023 Q18 JEE Mains Numerical
14 Mar 2026

(i) $\mathrm{X}(\mathrm{g}) \rightleftharpoons \mathrm{Y}(\mathrm{g})+\mathrm{Z}(\mathrm{g}) \quad \mathrm{K}_{\mathrm{p} 1}=3$

(ii) $\mathrm{A}(\mathrm{g}) \rightleftharpoons 2 \mathrm{~B}(\mathrm{g}) \quad \mathrm{K}_{\mathrm{p} 2}=1$

If the degree of dissociation and initial concentration of both the reactants $\mathrm{X}(\mathrm{g})$ and $\mathrm{A}(\mathrm{g})$ are equal, then the ratio of the total pressure at equilibrium $\left(\frac{p_{1}}{p_{2}}\right)$ is equal to $\mathrm{x}: 1$. The value of $\mathrm{x}$ is _____________ (Nearest integer)

2023 Q19 JEE Mains Numerical
14 Mar 2026

For reaction : $\mathrm{SO}_{2}(\mathrm{~g})+\frac{1}{2} \mathrm{O}_{2}(\mathrm{~g}) \rightleftharpoons \mathrm{SO}_{3}(\mathrm{~g})$

$\mathrm{K}_{\mathrm{p}}=2 \times 10^{12}$ at $27^{\circ} \mathrm{C}$ and $1 \mathrm{~atm}$ pressure. The $\mathrm{K}_{\mathrm{c}}$ for the same reaction is ____________ $\times 10^{13}$. (Nearest integer)

(Given $\mathrm{R}=0.082 \mathrm{~L} \mathrm{~atm} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$)

2023 Q20 JEE Mains Numerical
14 Mar 2026
Consider the following equation:

$2 \mathrm{SO}_{2}(g)+\mathrm{O}_{2}(g) \rightleftharpoons 2 \mathrm{SO}_{3}(g), \Delta H=-190 \mathrm{~kJ}$

The number of factors which will increase the yield of $\mathrm{SO}_{3}$ at equilibrium from the following is _______.

A. Increasing temperature

B. Increasing pressure

C. Adding more $\mathrm{SO}_{2}$

D. Adding more $\mathrm{O}_{2}$

E. Addition of catalyst
2023 Q21 JEE Mains Numerical
14 Mar 2026

At 298 K

$\mathrm{N_2~(g)+3H_2~(g)\rightleftharpoons~2NH_3~(g),~K_1=4\times10^5}$

$\mathrm{N_2~(g)+O_2~(g)\rightleftharpoons~2NO~(g),~K_2=1.6\times10^{12}}$

$\mathrm{H_2~(g)+\frac{1}{2}O_2~(g)\rightleftharpoons~H_2O~(g),~K_3=1.0\times10^{-13}}$

Based on above equilibria, then equilibrium constant of the reaction, $\mathrm{2NH_3(g)+\frac{5}{2}O_2~(g)\rightleftharpoons~2NO~(g)+3H_2O~(g)}$ is ____________ $\times10^{-33}$ (Nearest integer).

2023 Q22 JEE Mains Numerical
14 Mar 2026

Water decomposes at 2300 K

$\mathrm{H_2O(g)\to H_2(g)+\frac{1}{2}O_2(g)}$

The percent of water decomposing at 2300 K and 1 bar is ___________ (Nearest integer).

Equilibrium constant for the reaction is $2\times10^{-3}$ at 2300 K.

2023 Q23 JEE Mains Numerical
14 Mar 2026

Consider the following reaction approaching equilibrium at 27$^\circ$C and 1 atm pressure

$\mathrm{A+B}$ $\mathrel{\mathop{\kern0pt\rightleftharpoons} \limits_{{k_r} = {{10}^2}}^{{k_f} = {{10}^3}}} $ $\mathrm{C+D}$

The standard Gibb's energy change $\mathrm{(\Delta_r G^\theta)}$ at 27$^\circ$C is ($-$) ___________ kJ mol$^{-1}$ (Nearest integer).

(Given : $\mathrm{R=8.3~J~K^{-1}~mol^{-1}}$ and $\mathrm{\ln 10=2.3}$)

2023 Q24 JEE Advanced Numerical
14 Mar 2026
The plot of $\log k_f$ versus $1 / T$ for a reversible reaction $\mathrm{A}(\mathrm{g}) \rightleftharpoons \mathrm{P}(\mathrm{g})$ is shown.

JEE Advanced 2023 Paper 1 Online Chemistry - Chemical Equilibrium Question 3 English
Pre-exponential factors for the forward and backward reactions are $10^{15} \mathrm{~s}^{-1}$ and $10^{11} \mathrm{~s}^{-1}$, respectively. If the value of $\log K$ for the reaction at $500 \mathrm{~K}$ is 6 , the value of $\left|\log k_b\right|$ at $250 \mathrm{~K}$ is ______.

$ \begin{aligned} & {[K=\text { equilibrium constant of the reaction }} \\\\ & k_f=\text { rate constant of forward reaction } \\\\ & \left.k_b=\text { rate constant of backward reaction }\right] \end{aligned} $
2022 Q25 JEE Mains Numerical
14 Mar 2026

At $600 \mathrm{~K}, 2 \mathrm{~mol}$ of $\mathrm{NO}$ are mixed with $1 \mathrm{~mol}$ of $\mathrm{O}_{2}$.

$2 \mathrm{NO}_{(\mathrm{g})}+\mathrm{O}_{2}(\mathrm{g}) \rightleftarrows 2 \mathrm{NO}_{2}(\mathrm{g})$

The reaction occurring as above comes to equilibrium under a total pressure of 1 atm. Analysis of the system shows that $0.6 \mathrm{~mol}$ of oxygen are present at equilibrium. The equilibrium constant for the reaction is ________. (Nearest integer)

2022 Q26 JEE Mains Numerical
14 Mar 2026

At $298 \mathrm{~K}$, the equilibrium constant is $2 \times 10^{15}$ for the reaction :

$\mathrm{Cu}(\mathrm{s})+2 \mathrm{Ag}^{+}(\mathrm{aq}) \rightleftharpoons \mathrm{Cu}^{2+}(\mathrm{aq})+2 \mathrm{Ag}(\mathrm{s})$

The equilibrium constant for the reaction

$ \frac{1}{2} \mathrm{Cu}^{2+}(\mathrm{aq})+\mathrm{Ag}(\mathrm{s}) \rightleftharpoons \frac{1}{2} \mathrm{Cu}(\mathrm{s})+\mathrm{Ag}^{+}(\mathrm{aq}) $

is $x \times 10^{-8}$. The value of $x$ is _____________. (Nearest Integer)

2022 Q27 JEE Mains Numerical
14 Mar 2026

A box contains 0.90 g of liquid water in equilibrium with water vapour at 27$^\circ$C. The equilibrium vapour pressure of water at 27$^\circ$C is 32.0 Torr. When the volume of the box is increased, some of the liquid water evaporates to maintain the equilibrium pressure. If all the liquid water evaporates, then the volume of the box must be __________ litre. [nearest integer]

(Given : R = 0.082 L atm K$-$1 mol$-$1)

(Ignore the volume of the liquid water and assume water vapours behave as an ideal gas.)

2022 Q28 JEE Mains Numerical
14 Mar 2026

2NOCl(g) $\rightleftharpoons$ 2NO(g) + Cl2(g)

In an experiment, 2.0 moles of NOCl was placed in a one-litre flask and the concentration of NO after equilibrium established, was found to be 0.4 mol/L. The equilibrium constant at 30$^\circ$C is ______________ $\times$ 10$-$4.

2022 Q29 JEE Mains Numerical
14 Mar 2026

40% of HI undergoes decomposition to H2 and I2 at 300 K. $\Delta$G$^\Theta $ for this decomposition reaction at one atmosphere pressure is __________ J mol$-$1. [nearest integer]

(Use R = 8.31 J K$-$1 mol$-$1 ; log 2 = 0.3010, ln 10 = 2.3, log 3 = 0.477)

2022 Q30 JEE Mains Numerical
14 Mar 2026

The standard free energy change ($\Delta$G$^\circ$) for 50% dissociation of N2O4 into NO2 at 27$^\circ$C and 1 atm pressure is $-$ x J mol$-$1. The value of x is ___________. (Nearest Integer)

[Given : R = 8.31 J K$-$1 mol$-$1, log 1.33 = 0.1239 ln 10 = 2.3]

2022 Q31 JEE Mains Numerical
14 Mar 2026

PCl5 dissociates as

PCl5(g) $\rightleftharpoons$ PCl3(g) + Cl2(g)

5 moles of PCl5 are placed in a 200 litre vessel which contains 2 moles of N2 and is maintained at 600 K. The equilibrium pressure is 2.46 atm. The equilibrium constant Kp for the dissociation of PCl5 is __________ $\times$ 10$-$3. (nearest integer)

(Given : R = 0.082 L atm K$-$1 mol$-$1; Assume ideal gas behaviour)

2022 Q32 JEE Mains Numerical
14 Mar 2026

2O3(g) $\rightleftharpoons$ 3O2(g)

At 300 K, ozone is fifty percent dissociated. The standard free energy change at this temperature and 1 atm pressure is ($-$) ____________ J mol$-$1. (Nearest integer)

[Given : ln 1.35 = 0.3 and R = 8.3 J K$-$1 mol$-$1]

2021 Q33 JEE Mains Numerical
14 Mar 2026
When 5.1 g of solid NH4HS is introduced into a two litre evacuated flask at 27$^\circ$C, 20% of the solid decomposes into gaseous ammonia and hydrogen sulphide. The Kp for the reaction at 27$^\circ$C is x $\times$ 10$-$2. The value of x is _____________. (Integer answer) [Given R = 0.082 L atm K$-$1 mol$-$]
2021 Q34 JEE Mains Numerical
14 Mar 2026
The number of moles of NH3, that must be added to 2L of 0.80 M AgNO3 in order to reduce the concentration of Ag+ ions to 5.0 $\times$ 10$-$8 M (Kformation for [Ag(NH3)2]+ = 1.0 $\times$ 108) is ____________. (Nearest integer)

[Assume no volume change on adding NH3]
2021 Q35 JEE Mains Numerical
14 Mar 2026
The equilibrium constant Kc at 298 K for the reaction A + B $\rightleftharpoons$ C + D is 100. Starting with an equimolar solution with concentrations of A, B, C and D all equal to 1M, the equilibrium concentration of D is ___________ $\times$ 10$-$2 M. (Nearest integer)
2021 Q36 JEE Mains Numerical
14 Mar 2026
The reaction rate for the reaction

[PtCl4]2$-$ + H2O $\rightleftharpoons$ [Pt(H2O)Cl3]$-$ + Cl$-$

was measured as a function of concentrations of different species. It was observed that ${{ - d\left[ {{{\left[ {PtC{l_4}} \right]}^{2 - }}} \right]} \over {dt}} = 4.8 \times {10^{ - 5}}\left[ {{{\left[ {PtC{l_4}} \right]}^{2 - }}} \right] - 2.4 \times {10^{ - 3}}\left[ {{{\left[ {Pt({H_2}O)C{l_3}} \right]}^ - }} \right]\left[ {C{l^ - }} \right]$.

where square brackets are used to denote molar concentrations. The equilibrium constant Kc = ____________ . (Nearest integer)
2021 Q37 JEE Mains Numerical
14 Mar 2026
The OH$-$ concentration in a mixture of 5.0 mL of 0.0504 M NH4Cl and 2 mL of 0.0210 M NH3 solution is x $\times$ 10$-$6 M. The value of x is ___________. (Nearest integer)

[Given Kw = 1 $\times$ 10$-$14 and Kb = 1.8 $\times$ 10$-$5]
2021 Q38 JEE Mains Numerical
14 Mar 2026
The equilibrium constant for the reaction

A(s) $\rightleftharpoons$ M(s) + ${1 \over 2}$O2(g)

is Kp = 4. At equilibrium, the partial pressure of O2 is _________ atm. (Round off to the nearest integer)
2021 Q39 JEE Mains Numerical
14 Mar 2026
PCl5 $\rightleftharpoons$ PCl3 + Cl2

Kc = 1.844

3.0 moles of PCl5 is introduced in a 1 L closed reaction vessel at 380 K. The number of moles of PCl5 at equilibrium is ______________ $\times$ 10$-$3. (Round off to the Nearest Integer)
2021 Q40 JEE Mains Numerical
14 Mar 2026
Assuming that Ba(OH)2 is completely ionised in aqueous solution under the given conditions the concentration of H3O+ ions in 0.005 M aqueous solution of Ba(OH)2 at 298 K is ______________ $\times$ 10$-$12 mol L$-$1. (Nearest integer)
2021 Q41 JEE Mains Numerical
14 Mar 2026
For the reaction

A + B $\rightleftharpoons$ 2C

the value of equilibrium constant is 100 at 298 K. If the initial concentration of all the three species is 1 M each, then the equilibrium concentration of C is x $\times$ 10$-$1 M. The value of x is ____________. (Nearest integer)
2021 Q42 JEE Mains Numerical
14 Mar 2026
Value of KP for the equilibrium reaction

N2O4(g) $\rightleftharpoons$ 2NO2(g) at 288 K is 47.9. The KC for this reaction at same temperature is ____________. (Nearest integer)

(R = 0.083 L bar K$-$1 mol$-$1)
2021 Q43 JEE Mains Numerical
14 Mar 2026
2SO2(g) + O2(g) $\rightleftharpoons$ 2SO3(g)

In an equilibrium mixture, the partial pressures are

PSO3 = 43 kPa; PO2 = 530 Pa and PSO2 = 45 kPa. The equilibrium constant KP = ___________ $\times$ 10$-$2. (Nearest integer)
2021 Q44 JEE Mains Numerical
14 Mar 2026
The gas phase reaction $2A(g) \rightleftharpoons {A_2}(g)$ at 400 K has $\Delta$Go = + 25.2 kJ mol-1.

The equilibrium constant KC for this reaction is ________ $\times$ 10$-$2. (Round off to the Nearest Integer).

[Use : R = 8.3 J mol$-$1 K$-$1, ln 10 = 2.3 log10 2 = 0.30, 1 atm = 1 bar]

[antilog ($-$0.3) = 0.501]
2021 Q45 JEE Mains Numerical
14 Mar 2026
Consider the reaction

$N_{2}O_{4}\left( g\right) \rightleftharpoons 2NO_{2}\left( g\right) $

The temperature at which KC = 20.4 and KP = 600.1, is ____________ K. (Round off to the Nearest Integer). [Assume all gases are ideal and R = 0.0831 L bar K$-$1 mol$-$1]
2021 Q46 JEE Mains Numerical
14 Mar 2026
0.01 moles of a weak acid HA (Ka = 2.0 $\times$ 10$-$6) is dissolved in 1.0 L of 0.1 M HCl solution. The degree of dissociation of HA is __________ $\times$ 10$-$5 (Round off to the Nearest Integer).

[Neglect volume change on adding HA. Assume degree of dissociation <<1 ]
2021 Q47 JEE Mains Numerical
14 Mar 2026
For the reaction $A(g) \rightleftharpoons B(g)$ at 495 K, $\Delta$rG$^\circ$ = $-$9.478 kJ mol$-$1.
If we start the reaction in a closed container at 495 K with 22 millimoles of A, the amount of B in the equilibrium mixture is ____________ millimoles.
(Round off to the Nearest Integer). [R = 8.314 J mol$-$1 K$-$1; ln 10 = 2.303]
2021 Q48 JEE Mains Numerical
14 Mar 2026
A homogeneous ideal gaseous reaction $A{B_{2(g)}} \rightleftharpoons {A_{(g)}} + 2{B_{(g)}}$ is carried out in a 25 litre flask at 27$^\circ$C. The initial amount of AB2 was 1 mole and the equilibrium pressure was 1.9 atm. The value of Kp is x $\times$ 10$-$2. The value of x is _________. (Integer answer)

[R = 0.08206 dm3atm K$-$1mol$-$1]
2021 Q49 JEE Mains Numerical
14 Mar 2026
The stepwise formation of ${\left[ {Cu{{\left( {N{H_3}} \right)}_4}} \right]^{2 + }}$ is given below:

JEE Main 2021 (Online) 24th February Morning Shift Chemistry - Chemical Equilibrium Question 78 English
The value of stability constants K1, K2, K3 and K4 are 104, 1.58 x 103, 5 x 102 and 102 respectively.
The overall equilibrium constants for dissociation of ${\left[ {Cu{{\left( {N{H_3}} \right)}_4}} \right]^{2 + }}$ is x $ \times $ 10-12.
The value of x is ________. (Rounded off to the nearest integer)
2021 Q50 JEE Mains Numerical
14 Mar 2026
At 1990 K and 1 atm pressure, there are equal number of Cl2, molecules and Cl atoms in the reaction mixture. The value of Kp for the reaction Cl2 (g) $ \rightleftharpoons $ 2Cl(g) under the above conditions is x $ \times $ 10-1.
The value of x is _______. (Rounded off to the nearest integer)