Question

If equilibrium constant for reaction 2AB ⇌ $A _ { 2 } + B _ { 2 }$ , is 49, then the equilibrium constant for reaction

AB⇌ $\frac { 1 } { 2 } A _ { 2 } + \frac { 1 } { 2 } B _ { 2 }$ , will be

• A. 7
• B. 20
• C. 49
• D. 21

Answer 1

Answer: (A)

7

Answer 2

2AB ⇌ $A _ { 2 } + B _ { 2 }$

$K _ { c } = \frac { \left[ A _ { 2 } \right] \left[ B _ { 2 } \right] } { [ A B ] ^ { 2 } } = 49$

For reaction AB ⇌ $\frac { 1 } { 2 } A _ { 2 } + \frac { 1 } { 2 } B _ { 2 }$

$K _ { c } ^ { \prime } = \frac { \left[ A _ { 2 } \right] ^ { 1 / 2 } \left[ B _ { 2 } \right] ^ { 1 / 2 } } { [ A B ] }$

$K _ { c } ^ { \prime } = \sqrt { K _ { c } } = \sqrt { 49 } = 7$