AIPMT 2010 Physics and Chemistry Paper

(a) Reimer - Tiemann reaction,(Here, a new C - C bond is formed.)
(b) Cannizaro reaction,
(No new C−C bond is formed in this reaction.)
(c) Wrutz reaction,
2‌RX+ dry Na‌

‌ Ether ‌

──────▶

‌R−R
(one new C−C bond is formed.)
(d) Friedel - crafts acylation,Thus, among the given reactions, only cannizaro reaction does not involve the formation of a new C - C bond.