An answer that makes reference to the following points:
- (M1) reagent for step 1 - magnesium and (dry) ether
(1) (reacting with bromobenzene)
- (M2) first intermediate - phenyl magnesium bromide
(1)
- (M3) reagent for step 2 - phenyl magnesium bromide with carbon dioxide / CO2 and (followed by hydrolysis with) dilute acid / H+ or methanal and dilute acid / H+then oxidation
(1)
- (M4) second intermediate - benzoic acid
(1)
- (M5) reagent for step 3 - phosphorus(V) chloride /
(1) PCl5
(1)
- (M6) third intermediate - benzoyl chloride
-(M7) reagent for step 4 - ammonia / NH3 added to an
(1) acyl chloride
COMMENT Allow the use of ammonia with benzoic acid if there is clear evidence of the ammonium salt being dehydrated. M5 to M7 can then be awarded, otherwise the do not award applies