Degree of unsaturation present in compound (A + B + C) is ?

Answer

A + B + C = 17

Explanation

(A) `Ph-Ch=CH-CO_(2)H " " ` DBE = Double bond equivalent
(Perkin condensation ) `" " DBE = (C+1) - "("(H+ X-N)/(2)")"`
(B) `Ph-CH=CH-overset(OH)overset(|)(CH)-CH_(3) " " DBE = 5`
(Mearwein - Pandorf-verley reduction )
(C) `Ph-CH=CH - CO_(2)Na + CHI_(3) " " DBE = 6`
(Iodoform test )
Sum A + B + C = 17