Q.Resorcinol on distillation with zinc dust gives
A. Cyclohexane
B. Benzene
C. Toluene
D. Benzene-1, 3-diol

Step 1. Recall the reaction. Section 11.4.4 states that phenol, heated with zinc dust, is reduced to benzene, with the -OH group removed and zinc oxide formed as the by-product.

Step 2. Extend to resorcinol. Resorcinol is benzene-1,3-diol -- a dihydric phenol, i.e. a benzene ring carrying two -OH groups instead of phenol's one. Zinc-dust distillation is a general reduction of every phenolic -OH on the ring, not something limited to monohydric phenol specifically, so both of resorcinol's -OH groups are removed in the same way, again leaving the plain, unsubstituted benzene ring. …

Extending section 11.4.4's stated phenol + Zn dust -> benzene reduction to a dihydric phenol (resorcinol), recognising that Zn-dust distillation re …

• Confusing zinc-dust reduction (removes -OH, keeps the aromatic ring) with catalytic hydrogenation (H2/Ni, keeps -OH, saturates the ring to give cyclohexanol) -- these are two different reactions in the same section with opposite selectivity. …