# The decomposition of Cl2O7 at 400K in gas phase to Cl2 and O2 is a first order reaction.

(i) After 55s at 400K, the pressure of Cl2O7 falls from 0.062 to 0.044 atm. Calculate the

rate constant.

(ii) Calculate the pressure of Cl2O7 after 100s of decomposition at this temperature.

(i) After 55s at 400K, the pressure of Cl2O7 falls from 0.062 to 0.044 atm. Calculate the

rate constant.

(ii) Calculate the pressure of Cl2O7 after 100s of decomposition at this temperature.

### Asked by Bholanath Beura | 11th Sep, 2014, 09:40: PM

###
(i) For first order reaction

k= 2.303 log( a /a-x) ...................(1)

t

Here, a = 0.062 atm

a-x = 0.044 atm

t = 55s

k=2.303 log 0.062 = 6.24 x 10^{-3}s^{-1}

55 0.044

(ii) To calculate a-x when t = 100s, a= 0.062 atm, using equation (1)

So, 6.24 x 10^{-3}s^{-1 }= 2.303 log( a /a-x)

t

So a-x =0.033 atm

(i) For first order reaction

k= 2.303 log( a /a-x) ...................(1)

t

Here, a = 0.062 atm

a-x = 0.044 atm

t = 55s

k=2.303 log 0.062 = 6.24 x 10^{-3}s^{-1}

55 0.044

(ii) To calculate a-x when t = 100s, a= 0.062 atm, using equation (1)

So, 6.24 x 10^{-3}s^{-1 }= 2.303 log( a /a-x)

t

So a-x =0.033 atm

### Answered by Vaibhav Chavan | 12th Sep, 2014, 09:11: AM

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