A mixture of formic acid and oxalic acid is heated with concentrated `H_(2)SO_(4)`. The gas produced is collected and on its treatment with KOH solution the volume of the gas decreased by one-sixth. Calculate the molar ratio of the two acids in the original mixture.

Explanation

The decomposition of the acids takes place as follows:
`HCOOHrarrH_(2)O+CO`
`{:("a moles (say)","a moles","a moles"),(,"a vol.","a vol."):}}` after decomposition
`H_(2)C_(2)O_(4)rarrH_(2)O+CO+CO_(2)`
`{:("b moles (say)","b moles","b moles","b moles"),(,"b vol.","b vol.","b vol."):}}` after decomposition
`H_(2)O` is absorbed by `H_(2)SO_(4) and CO_(2)` is absorbed by KOH.
Thus, as given,
`("volume of "CO_(2))/("total volume of "(CO+CO_(2)))=(b)/(a+b+b)=(1)/(6)`
or `(a)/(b)=4`.
The molar ratio of HCOOH and `H_(2)C_(2)O_(4)=4:1`.