Question

adding equilibrium

Given the two reactions

H2S⇌HS−+H+,   K1 = 9.22×10⁻⁸, and

HS−⇌S2−+H+,   K2 = 1.12×10⁻¹⁹,

what is the equilibrium constant Kfinal for the following reaction?

S2−+2H+⇌H2S

Part B

Given the two reactions

PbCl2⇌Pb2++2Cl−,   K3 = 1.79×10⁻¹⁰, and

AgCl⇌Ag++Cl−,   K4 = 1.14×10⁻⁴,

what is the equilibrium constant Kfinal for the following reaction?

PbCl2+2Ag+⇌2AgCl+Pb2+

Express your answer numerically.

kfinal=

Enter your answer numerically.

Answer 1

Concepts and reason

The problem is based on the concept of chemical equilibrium.

A chemical reaction attains the stage of equilibrium when carried out in a closed vessel. In chemical equilibrium, the rate of the forward reaction becomes equal to the rate of backward reaction which results in no net changes in the concentration of reactants and products.

Fundamentals

As defined by the Law of chemical equilibrium, the ratio of the product of the reaction product raised to their respective stoichiometric coefficient to the product of the concentration of reactant raised to the respective stoichiometric coefficient has a constant value. The constant value is known as equilibrium constant. For the reaction, equilibrium constant is denoted by. The equilibrium constant is multiplicative in nature.

Part A

Consider the following reaction at equilibrium as:

…… (1)

…… (2)

Add equation (1) and equation (2), the chemical reaction is as follows:

…… (3)

Calculate the equilibrium constant for the reaction by using the relation as:

Substitute for and for in the above equation for the calculation of K as follows:

Consider the final reaction at equilibrium as:

Calculate the equilibrium constant for the reaction by using the relation as follows:

Substitute for K in the above equation for the calculation of as follows:

Part B

Consider the following reaction at equilibrium as:

…… (4)

…… (5)

Give coefficient 2 to equation (5), the balanced chemical reaction is as follows:

…… (6)

Calculate equilibrium constant for the equation (6) by using the relation as:

Substitute for in the equation for the calculation of as follows:

Consider the following equation at equilibrium as:

` …… (7)

Calculate the equilibrium constant for the reaction by using the relation as follows:

Substitute for in the equation for the calculation of as follows:

Consider the following reaction at equilibrium:

Calculate the equilibrium constantfor the reaction by using the relation as:

Substitute for and for in the above equation for the calculation of as:

Ans: Part A

The equilibrium constant for the reaction is.

Part B

The equilibrium constant for the reaction is.