A mixture of 2.3 g formic acid and 4.5 g oxalic acid is treated with conc. H2SO4. The evolved gaseous mixture is passed through KOH pellets. Weight (in g) of the remaining product at STP will be

KOH pellets absorbs CO2(g) obtained but not COH2SO4 absorbs water vapour.CO obtained from Formic acid HCOOH →CO(g) +H2O(g)46 gm of formic acid gives 28 gm of CO 2.3 gm gives =2.346×28=1.4 gm(COOH)2→CO(g) +CO2(g) +H2O(g)CO from Oxalic acid90 gm of Oxalic acid gives 28 gm of CO4.5 gm gives =4.590×28=1.4 gmTotal weight =1.4+1.4 = 2.8 gm