The reaction A `to`B follows first order reaction. The time taken for 0.8 mole of A to produce 0.6 mole of B is 1 hour. What is the time taken for conversion of 0.9 mole of A to produce 0.675 moles of B?

Options

A. 1 hour
B. 0.5 hour
C. 0.25 hour
D. 2 hours

Answer

A

Explanation

`A rarr B`
t = 0 0.8 0.6 + 0.6 mol
= 0.2 mol
Two half life's are involved in `0.8" mol "rarr 0.2" mol"`
In second case, `[A]_(t)=0.9-0.67=0.23" mol"`.
`0.9" mol"rarr 0.48" mol "rarr ~~ 0.23" mol"`
Again two half life's involve, so time taken to produce 0.67 mole B from 0.9 mol A is