Number of reactions which produces elemental carbon on dehydration with conc. $H_{2} SO_{4}$ .
(i) $C_{12} H_{22} O_{11} H_{2} SO_{4} conc.$
(ii) $C_{6} H_{12} O_{6} H_{2} SO_{4} conc$
(iii) $(COOH)_{2} H_{2} SO_{4} conc.$
(iv) $HCO_{2} H H_{2} SO_{4}^{OC} . conc.$

Question

Number of reactions which produces elemental carbon on dehydration with conc. $H_{2} SO_{4}$ .

(i) $C_{12} H_{22} O_{11} H_{2} SO_{4} conc.$

(ii) $C_{6} H_{12} O_{6} H_{2} SO_{4} conc$

(iii) $(COOH)_{2} H_{2} SO_{4} conc.$

(iv) $HCO_{2} H H_{2} SO_{4}^{OC} . conc.$

TestHub · Accepted Answer

Reactions (i) Sucrose and (ii) Glucose undergo "charring," where the acid removes water to leave behind a black mass of elemental carbon (C). Reaction (iii) Oxalic acid yields a mixture of CO and CO₂ gases instead of carbon. Reaction (iv) Formic acid dehydrates to produce CO gas.

Thus, only 2 reactions produce elemental carbon.

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