See image — AITS & Test Series Chemistry Question

💡 Solution & Explanation

(P) Br  CH2  CH2  CH2  3 C CH || O  Mg 2 3 3 THF BrMg (CH ) C CH || O     Intramolecular reaction makes cyclic compounds while Intermolecular reaction will go for polymerisation. Hence intramolecular cyclisation makes less decrease in entropy than intermolecular reaction. (Q) Five membered ring formation takes place faster than six membered ring. (R) The conformation C  C CH3 O N2 CH3 will not convert in to 3 3 O C C CH | CH    but C  C CH3 O CH3 N2 can form this because migration of methyl group will not become possible in first conformation. (S) Six membered ring is thermodynamically more stable than five membered ring.