`K_(a)` for formic acid and acetic acid are `2.1xx10^(-4)` and `1.1xx10^(-5)` respectively. The relative strength of acids is:

Options

A. `2:1`
B. `2.3:1`
C. `1:2.1`
D. `4.36:1`

Answer

D

Explanation

`:'` Relative strength of weak acids
`=sqrt(((K_(a_(1)))/(K_(a_(2)))xx(C_(1))/(C_(2))))`
Assume `C_(1)` and `C_(2)` are same. (Although not given)
`:.` Relative strength `= sqrt(((K_(a_(1)))/(K_(a_(2))))= sqrt(((2.1xx10^(-4))/(1.1xx10^(-5))))`
relative strength for HCOOH of `CH_(3)COOH=4.36:1`