`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. `10:1`
B. `1:10`
C. `1:sqrt(10)`
D. `sqrt(10):1`

Explanation

Relative strengths of weak acids=`sqrt(((K_(a_(1)))/(K_(a_(2)))))`
Assume `C_(1)` and `C_(2)` are same (Although not given).
Relative strength = `sqrt(((K_(a_(1)))/(K_(a_(2)))))=sqrt(((1.8xx10^(-4))/(1.8xx10^(-5))))`
Relative strength for `HCOOH` to `CH_(3)COOH=sqrt(10):1`