. 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

(a) 1.4

(b) 3.0

(c) 2.8

(d) 4.4

Best Answer

Correct Option is: (C)

HCOOH → CO + H2O (in presence of H2SO4)       … (1)

(COOH)2 → CO + CO2 + H2O      … (2)

Conc H2SO4 is a strong dehydrating agent.

Moles of HCOOH = 2.3/46 = 0.05 moles

Moles of (COOH)2 = 2.3/46 = 0.05 moles

From reaction (1), 

Number of CO formed= 0.05 moles

From reaction (2),

Number of CO formed= 0.05 moles

Number of CO2 formed= 0.05 moles

KOH pellets absorb all CO2. And H2O is absorbed by H2SO4. Thus CO is the remaining product.

Thus, weight of remaining product = 0.1 x 28 = 2.8g

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