What is the time required for a first order reaction to be 99 % complete, compared to the time taken for the reaction to be 90 % complete ?

Options

A. There is no change
B. Time taken is dounble
C. Time taken is triple
D. The time required is half the initial value

Answer

B

Explanation

Time for completion of 90 % of reaction
`t_(90%)=(2.303)/(k)"log"(100)/(100-90)`
`=(2.303)/(k)"log"(100)/(10)=(2.303)/(k)log10`
`=(2.303)/(k)`
Time for completion of 99 % reaction
`t_(99%)=(2.303)/(k)"log"(100)/(100-90)`
`=(2.303)/(k)"log"(100)/(1)=(2.303)/(k)xx2`
`:. (t_(99%))/(t_(90%))=2` .