The reaction `A(g)toB(g)+2C(g)` is a first order reaction with rate constant `2.772xx10^(-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 pressure and at 300 K?
a) `0.0125 M`
b) `0.025 M`
c) `0.05 M`
d) none of these

Explanation

We are given that, `k = (2.2 xx 10 ^(-5) sec ^(-1)) , t =90 min = 90 xx 60 = 5400` second
We are to find that, `(x)/(a) xx 100`
Using the relation ,` k = ( 2. 303 )/( l ) log "" (a)/((a -x ))`
`(2.2 xx 10 ^(-5) s ^(-1)) = ( 2. 303)/(5400 ) log "" (a)/(( a - c ))`
`(a)/( a - x ) = ` antilog `( 0. 0516) = 1. 126`
`(x)/(a) = 0. 112`
Percentage decomposition `= 0. 112 xx 100 = 11. 2 %`