Compound (X) [styrene] is subjected to the sequence of reactions as shown above: (i) Br_2/CHCl_3 (ii) NaNH_2 excess (iii) CH_3I (iv) H_2, Na/NH_3 (l), giving Major Product (Y). Molar mass of the major product (Y) formed is ______ g mol^ -1 . (Given molar mass in g mol^ -1 C:12, H: 1, O: 16)
B. 118
Addition of Br_2 to styrene (X) yields 1,2-dibromoethylbenzene. C_6H_5-CH=CH_2 Br_2/CHCl_3 C_6H_5-CH(Br)-CH_2(Br) Reaction with excess NaNH_2 causes double dehydrohalogenation followed by deprotonation of the terminal alkyne, forming sodium phenylacetylide. C_6H_5-CH(Br)-CH_2(Br) NaNH_2 (excess) C_6H_5-C C^- Na^+ Nucleophilic substitution with CH_3I yields 1-phenylpropyne. C_6H_5-C C^- Na^+ CH_3I C_6H_5-C C-CH_3 Reduction with Na/NH_3(l) reduces the internal alkyne to a trans-alkene without affecting the benzene ring. C_6H_5-C C-CH_3 Na/NH_3(l) C_6H_5-CH=CH-CH_3 The major product (Y) is trans-1-phenylpropene, which has the molecular formula C_9H_ 10 . Molar mass of C_9H_ 10 = (9 12) + (10 1) = 108 + 10 = 118 g mol ^ -1 . Answer: 118
Related: Chemistry — Hydrocarbons · All PYQ Banks