Chemical Equilibrium

2021 Q101 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 Q102 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 Q103 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 Q104 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 Q105 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 Q106 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 Q107 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 Q108 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 Q109 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 Q110 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 Q111 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 Q112 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 Q113 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 Q114 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 Q115 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 Q116 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 Q117 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)
2021 Q118 JEE Mains Numerical
14 Mar 2026
For the reaction A(g) $ \to $ B(g) the value of the equilibrium constant at 300 K and 1 atm is equal to 100.0. The value of $\Delta $rG for the reaction at 300 K and 1 atm in J mol-1 is – xR, where x is _______. (Rounded off to the nearest integer)
[R = 8.31 J mol–1K-1 and ln 10 = 2.3)
2021 Q119 AP-EAPCET MCQ
20 May 2026

At $60^{\circ} \mathrm{C}$, dinitrogen tetroxide is dissociated. Find it's standard free energy change at this temperature and one atmosphere. [Given $\log 1.33=0.1239$]

A.
$-650 \mathrm{~J} \mathrm{~mol}^{-1}$
B.
$-830 \mathrm{~J} \mathrm{~mol}^{-1}$
C.
$-790 \mathrm{~J~mol}^{-1}$
D.
$-875 \mathrm{~J} \mathrm{~mol}^{-1}$
2021 Q120 AP-EAPCET MCQ
20 May 2026

Le-Chatelier's principle is not applicable to

A.
$\mathrm{H}_2(g)+\mathrm{I}_2(g) \rightleftharpoons 2 \mathrm{HI}(g)$
B.
$\mathrm{Fe}(\mathrm{s})+\mathrm{S}(\mathrm{s}) \rightleftharpoons \mathrm{FeS}(\mathrm{s})$
C.
$\mathrm{N}_2(g)+3 \mathrm{H}_2(g) \rightleftharpoons 2 \mathrm{NH}_3(g)$
D.
$\mathrm{N}_2(g)+\mathrm{O}_2(g) \rightleftharpoons 2 \mathrm{NO}(g)$
2021 Q121 AP-EAPCET MCQ
20 May 2026

Using the data provided, find the value of equilibrium constant for the following reaction at $298 \mathrm{~K}$ and $1 \mathrm{~atm}$ pressure.

$\begin{aligned} \mathrm{NO}(g)+\frac{1}{2} \mathrm{O}_2(g) \rightleftharpoons & \mathrm{NO}_2(g) \\ \Delta_f H \mathrm{Y}[\mathrm{NO}(g)] & =90.4 \mathrm{~kJ} \mathrm{~mol}^{-1} \\ \Delta_f H \mathrm{Y}\left[\mathrm{NO}_2(g)\right] & =32.48 \mathrm{~kJ} \mathrm{~mol}^{-1} \\ \Delta S Y a t ~298 \mathrm{~K} & =-70.8 \mathrm{~JK}^{-1} \mathrm{~mol}^{-1} \end{aligned}$

$[\operatorname{antilog}(0.50)=3162 \text { ] }$

A.
$3.162 \times 10^4$
B.
$3.162 \times 10^{-4}$
C.
$3.162 \times 10^6$
D.
$3.162 \times 10^7$
2021 Q122 AP-EAPCET MCQ
20 May 2026

Standard entropies of $X_2, Y_2$ and $X Y_3$ are 60, 40 and $50 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}$ respectively. At what temperature, the following reaction will be at equilibrium? [given: $\Delta H \Upsilon=-30 \mathrm{~kJ}$]

$\frac{1}{2} X_2+\frac{3}{2} Y_2 \rightleftharpoons X Y_3$

A.
500 K
B.
750 K
C.
1000 K
D.
1250 K
2021 Q123 AP-EAPCET MCQ
20 May 2026

For the reaction $\mathrm{SO}_2(g)+\frac{1}{2} \mathrm{O}_2(g) \rightleftharpoons \mathrm{SO}_3(g)$, the percentage yield of product at different pressure is shown in the figure. Then, which among the following is true?

AP EAPCET 2021 - 19th August Morning Shift Chemistry - Chemical Equilibrium Question 28 English

A.
Pressure has no effect
B.
$p_1 < p_2 < p_3$
C.
$p_1 > p_2 > p_3$
D.
$p_1=p_2=p_3 \neq 0$
2021 Q124 AP-EAPCET MCQ
20 May 2026

Which among the following denotes the correct relationship between $K_p$ and $K_c$ for the reaction, $2 A(g) \rightleftharpoons B(g)+C(g)$

A.
$K_p>K_c$
B.
$K_c>K_p$
C.
$K_c=\left(K_p\right)^2$
D.
$K_p=K_c$
2020 Q125 JEE Mains MCQ
14 Mar 2026
The value of KC is 64 at 800 K for the reaction

N2(g) + 3H2(g) ⇌ 2NH3(g)

The value of KC for the following reaction is :

NH3(g) ⇌ ${1 \over 2}$N2(g) + ${3 \over 2}$H2(g)
A.
8
B.
${1 \over 8}$
C.
${1 \over 4}$
D.
${1 \over {64}}$
2020 Q126 JEE Mains MCQ
14 Mar 2026
For the reaction

Fe2N(s) + ${3 \over 2}$H2(g) ⇌ 2Fe(s) + NH3(g)
A.
KC = Kp(RT)1/2
B.
KC = Kp(RT)-1/2
C.
KC = Kp(RT)
D.
KC = Kp(RT)3/2
2020 Q127 JEE Mains MCQ
14 Mar 2026
The variation of equilibrium constant with temperature is given below :

Temperature Equilibrium Constant
T1 = 25oC K1 = 10
T2 = 100oC K2 = 100

The values of $\Delta $Ho, $\Delta $Go at
T1 and $\Delta $Go at T2 (in kJ mol–1) respectively, are close to :
[Use R = 8.314 J K–1 mol–1]
A.
28.4, –5.71 and –14.29
B.
0.64, –7.14 and –5.71
C.
28.4, –7.14 and –5.71
D.
0.64, –5.71 and –14.29
2020 Q128 JEE Mains MCQ
14 Mar 2026
Consider the following reaction:

N2O4(g) ⇌ 2NO2(g); $\Delta $Ho = +58 kJ

For each of the following cases (a, b), the direction in which the equilibrium shifts is :
(a) Temperature is decreased.
(b) Pressure is increased by adding N2 at constant T.
A.
(a) towards reactant, (b) towards product
B.
(a) towards reactant, (b) no change
C.
(a) towards product, (b) towards reactant
D.
(a) towards product, (b) no change
2020 Q129 JEE Mains MCQ
14 Mar 2026
If the equilibrium constant for
A ⇌ B + C is $K_{eq}^{(1)}$ and that of
B + C ⇌ P is $K_{eq}^{(2)}$, the equilibrium
constant for A ⇌ P is :
A.
${{K_{eq}^{(1)}} \over {K_{eq}^{(2)}}}$
B.
${K_{eq}^{(1)}}$ + ${K_{eq}^{(2)}}$
C.
${K_{eq}^{(2)}}$ - ${K_{eq}^{(1)}}$
D.
${K_{eq}^{(1)}}$ ${K_{eq}^{(2)}}$
2020 Q130 JEE Mains MCQ
14 Mar 2026
For the equilibrium A ⇌ B , the variation of the rate of the forward (a) and reverse (b) reaction with time is given by :
A.
JEE Main 2020 (Online) 4th September Morning Slot Chemistry - Chemical Equilibrium Question 85 English Option 1
B.
JEE Main 2020 (Online) 4th September Morning Slot Chemistry - Chemical Equilibrium Question 85 English Option 2
C.
JEE Main 2020 (Online) 4th September Morning Slot Chemistry - Chemical Equilibrium Question 85 English Option 3
D.
JEE Main 2020 (Online) 4th September Morning Slot Chemistry - Chemical Equilibrium Question 85 English Option 4
2020 Q131 JEE Mains MCQ
14 Mar 2026
An open beaker of water in equilibrium with water vapour is in a sealed container. When a few grams of glucose are added to the beaker of water, the rate at which water molecules :
A.
leaves the solution increases
B.
leaves the vapour increases
C.
leaves the vapour decreases
D.
leaves the solution decreases
2020 Q132 JEE Mains MCQ
14 Mar 2026
In the figure shown below reactant A (represented by square) is in equilibrium with product B (represented by circle). The equilibrium constant is : JEE Main 2020 (Online) 9th January Evening Slot Chemistry - Chemical Equilibrium Question 87 English
A.
1
B.
2
C.
8
D.
4
2020 Q133 JEE Mains Numerical
14 Mar 2026
For a reaction X + Y ⇌ 2Z , 1.0 mol of X, 1.5 mol
of Y and 0.5 mol of Z were taken in a 1 L vessel and
allowed to react. At equilibrium, the concentration
of Z was 1.0 mol L–1. The equilibrium constant of reaction
is ${x \over {15}}$. The value of x is _________.
2020 Q134 JEE Advanced Numerical
14 Mar 2026
Consider the reaction,

A $\rightleftharpoons $ B

at 1000 K. At time t', the temperature of the system was increased to 2000 K and the system was allowed to reach equilibrium. Throughout this experiment the partial pressure of A was maintained at 1 bar. Given, below is the plot of the partial pressure of B with time. What is the ratio of the standard Gibbs energy of the reaction at 1000 K to that at 2000 K?

JEE Advanced 2020 Paper 1 Offline Chemistry - Chemical Equilibrium Question 6 English
2020 Q135 TS-EAMCET MCQ
20 May 2026

Aqueous solution of ferric nitrate when mixed with aqueous solution of potassium thiocyanate gives red colour solution. The intensity of red colour becomes constant on attaining equilibrium.

Choose the correct statement when the following chemical is added to the above solution at equilibrium.

I. Oxalic acid

II. Mercuric chloride

A.

Both (I) and (II) will decrease the intensity of red colour.

B.

Both (I) and (II) will increase the intensity of red colour.

C.

(I) will increase but (II) will decrease the intensity of red colour.

D.

(I) will decrease but (II) will increase the intensity of red colour.

2020 Q136 TS-EAMCET MCQ
20 May 2026

For a given reaction, $2 A \rightleftharpoons B+C$, the equilibrium constant is $2 \times 10^{-3}$. If at any given time the composition of the reaction mixture is $[A]=[B]=[C]=6 \times 10^{-5} \mathrm{M}$; predict in which direction the reaction will proceed and the correct value for reaction quotient.

A.

Forward direction and 1.0

B.

Backward direction and 1.0

C.

Forward direction and $3 \times 10^{-5}$

D.

Backward direction and $3 \times 10^{-5}$

2020 Q137 TS-EAMCET MCQ
20 May 2026

For a reversible reaction $A \rightleftharpoons B$, pre-exponential factor is same for both the forward and backward reactions and has value of $20 \mathrm{~S}^{-1}$. If the enthalpy change along the forward reaction is $-41.5 \mathrm{~kJ} / \mathrm{mol}$, the value of equilibrium constant at 500 K is

A.

$e^{10}$

B.

$e^9$

C.

$e^8$

D.

$e^7$

2020 Q138 TS-EAMCET MCQ
20 May 2026

The vapour density of $\mathrm{N}_2 \mathrm{O}_4$ in $\mathrm{N}_2 \mathrm{O}_4 \rightleftharpoons 2 \mathrm{NO}_2$ is 40 . The degree of dissociation is

A.

1.25

B.

2.50

C.

1.50

D.

0.15

2020 Q139 TS-EAMCET MCQ
20 May 2026

What is the equilibrium constant $\left(K_C\right)$ for the given reaction?

$ \mathrm{N}_2+\mathrm{O}_2 \rightleftharpoons 2 \mathrm{NO} $

Where the equilibrium concentration of $\mathrm{N}_2, \mathrm{O}_2$ and NO are found to be $4 \times 10^{-3}, 3 \times 10^{-3}$ and $3 \times 10^{-3} \mathrm{M}$ respectively.

A.

0.750

B.

0.622

C.

$9 \times 10^{-3}$

D.

$12.8 \times 10^{-6}$

2020 Q140 BITSAT MCQ
11 Jun 2026

1.1 mole of A mixed with 2.2 moles of B and the mixture is kept in a 1 L flask and the equilibrium, A + 2B $\rightleftharpoons$ 2C + D is reached. If at equilibrium 0.2 mole of C is formed then the value of Kc will be

A.
0.1
B.
0.01
C.
0.001
D.
1
2020 Q141 BITSAT MCQ
11 Jun 2026

Sulphuric acid is a dibasic acid. It ionises in two stages and hence has two dissociation constants Ka1 and Ka2. Which of the following is the correct observation regarding Ka1 and Ka2 ?

A.
Ka1 > Ka2
B.
Ka1 < Ka2
C.
Ka1 = Ka2
D.
Ka1 = 1.2 $\times$ 10$-$2, Ka2 > 10
2019 Q142 JEE Mains MCQ
14 Mar 2026
The INCORRECT match in the following is :
A.
$\Delta $Go = 0, K = 1
B.
$\Delta $Go < 0, K < 1
C.
$\Delta $Go > 0, K < 1
D.
$\Delta $Go < 0, K > 1
2019 Q143 JEE Mains MCQ
14 Mar 2026
In which one of the following equilibria, Kp $ \ne $ KC ?
A.
2NO(g) ⇋ N2(g) + O2(g)
B.
2C(s) + O2(g) ⇋ 2CO(g)
C.
2HI(g) ⇋ H2(g) + I2(g)
D.
NO2(g) + SO2(g) ⇋ NO(g) + SO3(g)
2019 Q144 JEE Mains MCQ
14 Mar 2026
For the reaction,
2SO2(g) + O2(g) = 2SO3(g), $\Delta $H = –57.2 kJ mol–1 and KC = 1.7 × 1016
Which of the following statement is incorrect ?
A.
The equilibrium will shift in forward direction as the pressure increase.
B.
The addition of inert gas at constant volume will be not affect the equilibrium constant.
C.
The equilibrium constant is large suggestive of reaction going to completion and so no catalyst is required.
D.
The equilibrium constant decreases as the temperature increase.
2019 Q145 JEE Mains MCQ
14 Mar 2026
For the following reactions, equilibrium constants are given :

S(s) + O2(g) ⇋ SO2(g); K1 = 1052

2S(s) + 3O2(g) ⇋ 2SO3(g); K2 = 10129

The equilibrium constant for the reaction,

2SO2(g) + O2(g) ⇋ 2SO3(g) is :
A.
10181
B.
1025
C.
1077
D.
10154
2019 Q146 JEE Mains MCQ
14 Mar 2026
Two solids dissociate as follows –
JEE Main 2019 (Online) 12th January Morning Slot Chemistry - Chemical Equilibrium Question 92 English
The total pressure when both the solids dissociated simultaneously is -
A.
(x + y) atm
B.
$\left( {\sqrt {x + y} } \right)$ atm
C.
2$\left( {\sqrt {x + y} } \right)$ atm
D.
x2 + y2 atm
2019 Q147 JEE Mains MCQ
14 Mar 2026
In a chemical reaction,

JEE Main 2019 (Online) 12th January Morning Slot Chemistry - Chemical Equilibrium Question 93 English
the initial concentration of B was 1.5 times of the concentration of A, but the equilibrium concentrations of A and B were found to be equal. The equilibrium constant (K) for the aforesaid chemical reaction is -
A.
16
B.
1
C.
1/4
D.
4
2019 Q148 JEE Mains MCQ
14 Mar 2026
Consider the reaction
N2(g) + 3H2(g) $\rightleftharpoons$ 2NH3(g)

The equilibrium constant of the above reaction is Kp. If pure ammonia is left to dissociate, the partial pressure of ammonia at equilibrium is given by (Assume that PNH3 << Ptotal at equilibrium)
A.
${{{3^{{3 \over 2}}}{K_P^{{1 \over 2}}}{P^2}} \over 4}$
B.
${{K_P^{{1 \over 2}}{P^2}} \over 4}$
C.
${{{3^{{3 \over 2}}}{K_P^{{1 \over 2}}}{P^2}} \over 16}$
D.
${{K_P^{{1 \over 2}}{P^2}} \over 16}$
2019 Q149 JEE Mains MCQ
14 Mar 2026
5.1 g NH4SH is introduced in 3.0 L evacuated flask at 327ºC. 30% of the solid NH4SH decomposed to NH3 and H2S as gases . The Kp of the reaction at 327oC is (R = 0.082 L atm mol–1 K–1, Molar mass of S = 32 g mol–1 molar mass of N = 14 g mol–1)
A.
0.242 $ \times $ 10$-$4 atm2
B.
1 $ \times $ 10–4 atm2
C.
4.9 $ \times $ 10$-$3 atm2
D.
0.242 atm2
2019 Q150 JEE Mains MCQ
14 Mar 2026
The values of Kp/Kc for the following reactions at 300 K are, respectively : (At 300 K, RT = 24.62 dm3 atm mol–1)

N2(g) + O2(g)  $\rightleftharpoons$ 2 NO(g)

N2O4(g)  $\rightleftharpoons$   2 NO(g)

N2(g) + 3H2(g) $\rightleftharpoons$ 2 NH3(g)
A.
24.62 dm3 atm mol–1, 606.0 dm6 atm2 mol–2 1.65 $ \times $ 10–3 dm–6 atm–2 mol2
B.
1,4.1 $ \times $ 10–2 dm–3 atm–1 mol, 606 dm6 atm2 mol–2
C.
1,24.62 dm3 atm mol–1 , 1.65 $ \times $ 10–3 dm–6 atm –2 mol2
D.
1, 24.62 dm3 atm mol–1, 606.0 dm6 atm2 mol–2