Question

At a certain temperature the half life periodsfor catalytic decomposition of nh3. What will be the pressure when the half life period is 2.5 hours

Answer 1

Half life period of a reaction is indirectly proportional to the initial concentration.

⟹t

1/2

∝(1/C

0

n−1

)For first scenario, Half life = 4 years; Concentration = 50mm

⟹4=(1/50

n−1

)

For second scenario, Half life = 2 years; Concentration = 100mm

⟹2=(1/100

n−1

)

Ratio will be:

⟹4/2=(100/50)

n−1

⟹2=(2)

n−1

∴ n=2