The reaction A(g) `rarr` B(g) + 2C(g) is a first order reaction with rate constant `2.772 xx 10^(-3) S^(-1)` . Starting with 0.1 mole of A in 2 litre vessel, find the concentration of A after 250 sec when the reaction is allowed to take place at constant pressrue at 300 K.

Options

A. 0.0125 M
B. 0.025 M
C. 0.05 M
D. 0.125 M

Answer

A

Explanation

`t_(1//2) =(0.693)/(k)=(0.693)/(2.72xx10^(-3))=250 sec`
since volume is changing therefore half life remaining after 250 sec also final volume of the container
`v_(f)=(n_(f))/(n_(i))xxv_(i)=(0.05+0.15)/(0.1)xx2=4` litre `therefore` Final concentration of A=`(0.05)/(4)`=0.0125 M