For the self-ionisation (protonation) process liquid formic acid at `20^(@)`C.
`HCOOH+HCOOHto HCOOH_(2)^(+)+HCOO^(-)`
the equilibrium constant,
`K=([HCOOH_(2)^(+)][HCOO^(-)])/([HCOOH]^(2))=10^(-10)`
At `20^(@)`C, the density of liquid formic acid is 0.92 gm/mL.
The ionic prodcut of formic acid,`K=[HCOOH_(2)^(+)][HCOO^(-)]` is :

Options

A. `10^(-10)M^(2)`
B. `4.0xx10^(-8)M^(2)`
C. `2.5xx10^(-13)M^(2)`
D. `2.0xx10^(-9)M^(2)`

Answer

b