Law of Mass Action

Interactive Feed

JEE Advanced 2016

Comprehension Passage

X_{2}

to gaseous X at 298 K takes place according to the following equation :

X_{2} (g) ⇌ 2 X (g)

The standard reaction Gibbs energy,

Δ_{r} G^{\circ}

, of this reaction is positive. At the start of the reaction, there is one mole of

X_{2}

and no X. As the reaction proceeds, the number of moles of X formed is given by

β

. Thus,

β_{equilibrium}

is the number of moles of X formed at equilibrium. The reaction is carried out at a constant total pressure of 2 bar. Consider the gases to behave ideally. (Given :

R = 0.083 L bar K^{- 1} mol^{- 1}

)

Question 1:

The equilibrium constant $K_{P}$ for this reaction at 298 K, in terms of $β_{equilibrium}$ , is

(A)

\frac{8 β _{equilibrium}^{2}}{2 - β _{equilibrium}}

(B)

\frac{8 β _{equilibrium}^{2}}{4 - β _{equilibrium}^{2}}

(C)

\frac{4 β _{equilibrium}^{2}}{2 - β _{equilibrium}}

(D)

\frac{4 β _{equilibrium}^{2}}{4 - β _{equilibrium}^{2}}

Question 2:

The INCORRECT statement among the following , for this reaction, is

(A)

Decrease in the total pressure will result in formation of more moles of gaseous X

(B)

At the start of the reaction, dissociation of gaseous

X_{2}

takes place spontaneously

(C)

β_{equilibrium} = 0.7

(D)

K_{C} < 1

JEE Main 2019

LEVELJEE Advanced

5.1 g $NH_{4} SH$ is introduced in 3.0 L evacuated flask at $32 7^{\circ} C$ . 30\% of the solid $NH_{4} SH$ decomposed to $NH_{3}$ and $H_{2} S$ as gases. The $K_{p}$ of the reaction at $32 7^{\circ} C$ is ( $R = 0.082 atm mol^{- 1} K^{- 1}$ , molar mass of $S = 32 g mol^{- 1}$ , molar mass of $N = 14 g mol^{- 1}$ )

(A)

0.242 \times 1 0^{- 4} atm^{2}

(B)

0.242 atm^{2}

(C)

4.9 \times 1 0^{- 3} atm^{2}

(D)

1 \times 1 0^{- 4} atm^{2}

LEVELJEE Main

For the reaction, $C O (g) + C l_{2} (g) ⇌ C O C l_{2} (g)$ , the $K_{p} / K_{c}$ is equal to

(A)

1/ R T

(B)

R T

(C)

R T

(D)

1.0

JEE Main 2020

LEVELJEE Main

If the equilibrium constant for $A ⇌ B + C$ is $K_{e q}^{(1)}$ and that of $B + C ⇌ P$ is $K_{e q}^{(2)}$ , the equilibrium constant for $A ⇌ P$ is

(A)

K_{e q}^{(1)} / K_{e q}^{(2)}

(B)

K_{e q}^{(1)} + K_{e q}^{(2)}

(C)

K_{e q}^{(1)} K_{e q}^{(2)}

(D)

K_{e q}^{(2)} - K_{e q}^{(1)}

JEE Main 2021

LEVELJEE Advanced

The gas phase reaction $2 A (g) ⇌ A_{2} (g)$ at $400 K$ has $Δ G^{\circ} = + 25.2 kJ mol^{- 1}$ . The equilibrium constant $K_{C}$ for this reaction is ......... $\times 1 0^{- 2}$ . (Round off to the nearest integer). [Use : $R = 8.3 J mol^{- 1} K^{- 1}$ , $ln 10 = 2.3$ ] $lo g_{10} 2 = 0.30$ , $1 atm = 1 bar$ ] $[antilog (- 0.3) = 0.501]$

JEE Main 2019

LEVELJEE Main

Consider the following reversible chemical reactions, $A_{2} (g) + B_{2} (g) ⇌ 2 A B (g)$ ...(i) with equilibrium constant $K_{1}$ $6 A B (g) ⇌ 3 A_{2} (g) + 3 B_{2} (g)$ ...(ii) with equilibrium constant $K_{2}$ The relation between $K_{1}$ and $K_{2}$ is

(A)

K_{2} = K_{1}^{3}

(B)

K_{1} K_{2} = 3

(C)

K_{2} = K_{1}^{- 3}

(D)

K_{1} K_{2} = \frac{1}{3}

JEE Main 2019

LEVELJEE Main

For the following reactions, equilibrium constants are given : $S (s) + O_{2} (g) ⇌ SO_{2} (g); K_{1} = 1 0^{52}$ $2 S (s) + 3 O_{2} (g) ⇌ 2 SO_{3} (g); K_{2} = 1 0^{129}$ The equilibrium constant for the reaction, $2 SO_{2} (g) + O_{2} (g) ⇌ 2 SO_{3} (g)$ is

(A)

1 0^{25}

(B)

1 0^{77}

(C)

1 0^{154}

(D)

1 0^{181}

JEE Main 2021

LEVELJEE Main

For the reaction, $A (g) ⇌ B (g)$ at $495 K$ , $Δ_{r} G^{\circ} = - 9.478 kJ mol^{- 1}$ . 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). $[R = 8.314 J mol^{- 1} K^{- 1}, ln 10 = 2.303]$

JEE Main 2019

LEVELJEE Main

The values of $\frac{K _{p}}{K _{C}}$ for the following reactions at $300 K$ are, respectively (At $300 K$ , $R T = 24.62 dm^{3} atm mol^{- 1}$ ) $N_{2} (g) + O_{2} (g) ⇌ 2 NO (g)$ $N_{2} O_{4} (g) ⇌ 2 NO_{2} (g)$ $N_{2} (g) + 3 H_{2} (g) ⇌ 2 NH_{3} (g)$

(A)

1

24.62 dm^{3} atm mol^{- 1}

606.0 dm^{6} atm^{2} mol^{- 2}

(B)

1

24.62 dm^{3} atm mol^{- 1}

1.65 \times 1 0^{- 3} dm^{- 6} atm^{- 2} mol^{2}

(C)

24.62 dm^{3} atm mol^{- 1}

606.0 dm^{6} atm^{- 2} mol^{2}

1.65 \times 1 0^{- 3} dm^{- 6} atm^{- 2} mol^{2}

(D)

1

4.1 \times 1 0^{- 2} dm^{- 3} atm^{- 1} mol

606 dm^{6} atm^{2} mol^{- 2}

JEE Main 2019

LEVELJEE Main

In which one of the following equilibria, $K_{p} \neq = K_{c}$ ?

(A)

2 C (s) + O_{2} (g) ⇌ 2 CO (g)

(B)

2 HI (g) ⇌ H_{2} (g) + I_{2} (g)

(C)

NO_{2} (g) + SO_{2} (g) ⇌ NO (g) + SO_{3} (g)

(D)

2 NO (g) ⇌ N_{2} (g) + O_{2} (g)

JEE Main 2021

LEVELJEE Main

$PCl_{5} ⇌ PCl_{3} + Cl_{2}, K_{c} = 1.844$ $3.0$ moles of $PCl_{5}$ is introduced in a $1 L$ closed reaction vessel at $380 K$ . The number of moles of $PCl_{5}$ at equilibrium is ............ $\times 1 0^{- 3}$ . (Round off to the nearest integer)

JEE Main 2019

LEVELJEE Advanced

Two solids dissociate as follows: $A (s) ⇌ B (g) + C (g); K_{p_{1}} = x atm^{2}$ $D (s) ⇌ C (g) + E (g); K_{p_{2}} = y atm^{2}$ The total pressure when both the solids dissociate simultaneously is

(A)

x + y atm

(B)

x^{2} + y^{2} atm

(C)

(x + y) atm

(D)

2 (x + y) atm

LEVELJEE Main

An amount of solid $NH_{4} HS$ is placed in a flask already containing ammonia gas at a certain temperature and $0.50 atm$ pressure. Ammonium hydrogen sulphide decomposes to yield $NH_{3}$ and $H_{2} S$ gases in the flask. When the decomposition reaction reaches equilibrium, the total pressure in the flask rises to $0.84 atm$ . The equilibrium constant for the decomposition of $NH_{4} HS$ at this temperature is

(A)

0.11

(B)

0.17

(C)

0.18

(D)

0.30

LEVELBoard

What is the equilibrium expression for the reaction $P_{4} (s) + 5 O_{2} (g) ⇌ P_{4} O_{10} (s)$ ?

(A)

K_{c} = \frac{[ P _{4} O _{10} ]}{[ P _{4} ] [ O _{2} ] ^{5}}

(B)

K_{c} = \frac{[ P _{4} O _{10} ]}{5 [ P _{4} ] [ O _{2} ] ^{5}}

(C)

K_{c} = [O_{2}]^{5}

(D)

K_{c} = \frac{1}{[ O _{2} ] ^{5}}

JEE Main 2020

LEVELJEE Main

The value of $K_{C}$ is $64$ at $800 K$ for the reaction, $N_{2} (g) + 3 H_{2} (g) ⇌ 2 N H_{3} (g)$ The value of $K_{C}$ for the following reaction is $N H_{3} (g) ⇌ \frac{1}{2} N_{2} (g) + \frac{3}{2} H_{2} (g)$

(A)

\frac{1}{64}

(B)

8

(C)

\frac{1}{4}

(D)

\frac{1}{8}

JEE Main 2020

LEVELJEE Main

For the reaction, $Fe_{2} N (s) + \frac{3}{2} H_{2} (g) ⇌ 2 Fe (s) + NH_{3} (g)$

(A)

K_{c} = K_{p} (R T)

(B)

K_{c} = K_{p} (R T)^{- 1/2}

(C)

K_{c} = K_{p} (R T)^{1/2}

(D)

K_{c} = K_{p} (R T)^{3/2}

JEE Main 2021

LEVELJEE Main

Value of $K_{p}$ for the equilibrium reaction $N_{2} O_{4} (g) ⇌ 2 N O_{2} (g)$ at $288 K$ is $47.9$ . The $K_{c}$ for this reaction at same temperature is ...... (Nearest integer) ( $R = 0.083 L bar K^{- 1} mol^{- 1}$ )

JEE Main 2021

LEVELJEE Advanced

A homogeneous ideal gaseous reaction, $A B_{2} (g) ⇌ A (g) + 2 B (g)$ is carried out in a 25 L flask at 27°C. The initial amount of $A B_{2}$ was 1 mole and the equilibrium pressure was 1.9 atm. The value of $K_{p}$ is $x \times 1 0^{- 2}$ . The value of $x$ is ………… .

JEE Main 2021

LEVELJEE Main

For the reaction, $2 SO_{2} (g) + O_{2} (g) ⇌ 2 SO_{3} (g)$ In an equilibrium mixture, the partial pressures are $p_{SO_{3}} = 43 kPa$ ; $p_{O_{2}} = 530 Pa$ and $p_{SO_{2}} = 45 kPa$ . The equilibrium constant $K_{p} = \dots \times 1 0^{- 2}$ . (Nearest integer)

JEE Main 2020

LEVELJEE Main

In the figure shown below, reactant A (represented by square) is in equilibrium with product B (represented by circle). The equilibrium constant is

The equilibrium constant $K_{C}$ at 298 K for the reaction $A + B ⇌ C + D$ 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 ......... $\times 1 0^{- 2}$ M. (Nearest integer)

JEE Main 2020

LEVELJEE Main

For a reaction, $X + Y ⇌ 2 Z$ \n $1.0 mol$ 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 the reaction is $\frac{x}{15}$ . The value of $x$ is ......... .

LEVELJEE Advanced

The equilibrium constants $K_{p_{1}}$ and $K_{p_{2}}$ for the reactions $X ⇌ 2 Y$ and $Z ⇌ P + Q$ , respectively are in the ratio of $1 : 9$ . If the degree of dissociation of $X$ and $Z$ be equal, then the ratio of total pressure at these equilibria is

(A)

1 : 36

(B)

1 : 1

(C)

1 : 3

(D)

1 : 9

LEVELJEE Main

For the reaction, $2 NO_{2} (g) ⇌ 2 NO (g) + O_{2} (g)$ $[K_{c} = 1.8 \times 1 0^{- 6} at 18 4^{\circ} C, R = 0.00831 kJ / (mol K)]$ When $K_{p}$ and $K_{c}$ are compared at $18 4^{\circ} C$ it is found that

(A)

whether

K_{p}

is greater than, less than or equal to

K_{c}

depends upon the total gas pressure

(B)

K_{p} = K_{c}

(C)

K_{p}

is less than

K_{c}

(D)

K_{p}

is greater than

K_{c}

LEVELJEE Main

For the following three reactions I, II and III, equilibrium constants are given I. $C O (g) + H_{2} O (g) ⇌ C O_{2} (g) + H_{2} (g); K_{1}$ II. $C H_{4} (g) + H_{2} O (g) ⇌ C O (g) + 3 H_{2} (g); K_{2}$ III. $C H_{4} (g) + 2 H_{2} O (g) ⇌ C O_{2} (g) + 4 H_{2} (g); K_{3}$ Which of the following relations is correct?

(A)

K_{1} K_{2} = K_{3}

(B)

K_{2} K_{3} = K_{1}

(C)

K_{3} = K_{1} K_{2}

(D)

K_{3} K_{2}^{3} = K_{1}^{2}

Comprehension Passage

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } The equilibrium constant KP​ for this reaction at 298 K, in terms of βequilibrium​ , is

The INCORRECT statement among the following , for this reaction, is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } For the reaction, CO(g)+Cl2​(g)⇌COCl2​(g), the Kp​/Kc​ is equal to

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } If the equilibrium constant for A⇌B+C is Keq(1)​ and that of B+C⇌P is Keq(2)​, the equilibrium constant for A⇌P is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } In which one of the following equilibria, Kp​=Kc​?

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Two solids dissociate as follows: A(s)⇌B(g)+C(g);Kp1​​=x atm2 D(s)⇌C(g)+E(g);Kp2​​=y atm2 The total pressure when both the solids dissociate simultaneously is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } What is the equilibrium expression for the reaction P4​(s)+5O2​(g)⇌P4​O10​(s)?

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } 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)⇌21​N2​(g)+23​H2​(g)

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } For the reaction, Fe2​N(s)+23​H2​(g)⇌2Fe(s)+NH3​(g)

In the figure shown below, reactant A (represented by square) is in equilibrium with product B (represented by circle). The equilibrium constant is

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } For the reaction, 2NO2​(g)⇌2NO(g)+O2​(g) [Kc​=1.8×10−6 at 184∘C,R=0.00831 kJ/(mol K)] When Kp​ and Kc​ are compared at 184∘C it is found that

The equilibrium constant $K_{P}$ for this reaction at 298 K, in terms of $β_{equilibrium}$ , is

For the reaction, $C O (g) + C l_{2} (g) ⇌ C O C l_{2} (g)$ , the $K_{p} / K_{c}$ is equal to

If the equilibrium constant for $A ⇌ B + C$ is $K_{e q}^{(1)}$ and that of $B + C ⇌ P$ is $K_{e q}^{(2)}$ , the equilibrium constant for $A ⇌ P$ is

In which one of the following equilibria, $K_{p} \neq = K_{c}$ ?

Two solids dissociate as follows: $A (s) ⇌ B (g) + C (g); K_{p_{1}} = x atm^{2}$ $D (s) ⇌ C (g) + E (g); K_{p_{2}} = y atm^{2}$ The total pressure when both the solids dissociate simultaneously is

What is the equilibrium expression for the reaction $P_{4} (s) + 5 O_{2} (g) ⇌ P_{4} O_{10} (s)$ ?

The value of $K_{C}$ is $64$ at $800 K$ for the reaction, $N_{2} (g) + 3 H_{2} (g) ⇌ 2 N H_{3} (g)$ The value of $K_{C}$ for the following reaction is $N H_{3} (g) ⇌ \frac{1}{2} N_{2} (g) + \frac{3}{2} H_{2} (g)$

For the reaction, $Fe_{2} N (s) + \frac{3}{2} H_{2} (g) ⇌ 2 Fe (s) + NH_{3} (g)$

For the reaction, $2 NO_{2} (g) ⇌ 2 NO (g) + O_{2} (g)$ $[K_{c} = 1.8 \times 1 0^{- 6} at 18 4^{\circ} C, R = 0.00831 kJ / (mol K)]$ When $K_{p}$ and $K_{c}$ are compared at $18 4^{\circ} C$ it is found that