Law of Chemical Equilibrium and Equilibrium Constants

IMPORTANT

Law of Chemical Equilibrium and Equilibrium Constants: Overview

This topic covers concepts, such as, Law of Mass Action, Forward Rate Constant, Backward Rate Constant, Equilibrium Constant, Active Mass, Equilibrium Law or Law of Chemical Equilibrium & Equilibrium Equation etc.

Important Questions on Law of Chemical Equilibrium and Equilibrium Constants

EASY
IMPORTANT

 An expression for the backward rate constant of the reaction, aA+bB            cC+dD is

HARD
IMPORTANT

The reaction A (g)+B (g)C (g)+D (g) is elementary 2nd order reaction opposed by elementary secondary order reaction. When started with equimolar amounts of A and B, at equilibrium, it is found that the concentration of A is twice that of C . Specific rate constant for forward reaction is 2×10-3mol-1Lsec-1. The specific rate constant for backward reaction is

EASY
IMPORTANT

For the reaction, 2SO2(g)+O2(g)2SO3(g)
What is Kc when the equilibrium concentration of [SO2]=0.60M, [O2]=0.82M and [SO3]=1.90M?

HARD
IMPORTANT

The reaction

CaCO3sCaOs+CO2g

is in equilibrium in a closed vessel at 298 K. The partial pressure (in atm) of CO2g in the reaction vessel is closest to:

[Given: The change in Gibbs energies of formation at 298 K and 1 bar for

CaO(s)=-603.501 kJ mol-1

CO2g=-394.389 kJ mol-1

CaCO3s=-1128.79 kJ mol-1

Gas constant R=8.314 J K-1 mol-1]

HARD
IMPORTANT

Find the number of reaction which will be favoured in backward direction:

A EtOH+KOHEtOK+H2O

B

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C

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D

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MEDIUM
IMPORTANT

Find the approximate value of Kc for the given equilibrium reaction, when 2 moles of SO2 and 1 mole of O2 are allowed to react in a container of capacity 2 L and the following equilibrium is established:

2SO2(g)+O2(g)2SO3(g), given that the equilibrium mixture requires 200 mL of 0.1 M acidified K2Cr2O7 solution.

EASY
IMPORTANT

When the two reactants A and B are mixed to give products C and D, the reaction quotient Q at the initial stage of the reaction 

MEDIUM
IMPORTANT

For the given reaction at equilibrium, KP=2.0×1010/bar at 450K.         

2SO2g+O2g2SO3g

 Kc at this temperature is n×1011Lmol-1. Find value of n. (Round off n up to the one decimal place)

MEDIUM
IMPORTANT

For the following equilibrium, Kc= 6.3×1014 at 1000K.
NOg+O3gNO2g+O2g
Both the forward and reverse reactions in the equilibrium are elementary bimolecular reactions. What is Kc for the reverse reaction in terms of n×10-15. Find value of n. 

Enter your answer from these options : (0.5/1.587/1.287/1.785)

MEDIUM
IMPORTANT

Equilibrium constant for reaction NH4OHaq+H+aqNH4+aq+H2Ol is 1.8 × 109. Hence equilibrium constant for ionization NH3+H2ONH4+aq+OH-aq  is x×10-6.The value of 'x' is:

MEDIUM
IMPORTANT

For the following gaseous equilibrium, N2O4g2NO2g

Kp is found to be equal to Kc. This is attained when the temperature is:

EASY
IMPORTANT

For the reaction, A(s) + 2B(g) 2C(g) + D(l) at TK
Find the value of Kp when the equilibrium contains 25% of B(g) by volume of the gaseous species.

EASY
IMPORTANT

For the reaction, 2SO2(g)+O2(g)2SO3(g)
What is Kc when the equilibrium concentration of [SO2]=0.60M, [O2]=0.82M and [SO3]=1.90M?

EASY
IMPORTANT

The decay profiles of three radioactive species A, B and C are given below:

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These profiles imply that the decay constants kA, kB and kC follow the order

EASY
IMPORTANT

The concentrations of the reactant A in the reaction AB at different times are given below

Concentration (M) Time (Minutes)
0.069 0
0.052 17
0.035 34
0.018 51


The rate constant of the reaction according to the correct order of reaction is:

MEDIUM
IMPORTANT

Nine volumes of a gaseous mixture consisting of gaseous organic compound A and just sufficient amount of oxygen required for complete combustion yielded on burning four volumes of CO2, six volumes of water vapour and two volumes of N2, all volumes measured at the same temperature and pressure. If the compound contains C, H and N only, the molecular formula of the compound A is:

EASY
IMPORTANT

In a chemical reaction, the rate constant for the backward reaction is 7.5 × 10–4 and the equilibrium constant is 1.5. The rate constant for the forward reaction is -

EASY
IMPORTANT

The rate constant at 25°C for the reaction of NH4+ & OH to form NH4OH is 4 × 1010 M1sec-1 & ionisation constant of aq. NH3 is 1.8 × 105. The rate constant of proton transfer to NH3 is -

EASY
IMPORTANT

In a chemical reaction, the rate constant for the backward reaction is 7.5 × 104 and the equilibrium constant is 1.5. The rate constant for the forward reaction is -

MEDIUM
IMPORTANT

In reversible reaction A + BC + D, rate constant of forward reaction is 105 & rate constant of backward reaction is 103. Equilibrium constant KC is -