Which of the following will give alkyne on reaction of phosphorous-penta -chloride followed by dehydrohalogenation with Sodamide ?

detailed solution

Correct option is B

aldehydes or ketones can form gem dihalides on reaction with PCl5 . The gem dihalides having  hydrogens will undergo double dehydrohalogenation to form Alkynes.          Only acetophenone will form gem dihalide with PCl5 . Further, it will undergo dehydrohalogenation with  NaNH2 and forms phenyl-Acetylene.          Other compounds will form halogen derivative but will not participate in dehydrohalogenation due to lack of alpha hydrogens.