How many alpha hydrogen are present in benzyl methyl ketone?
a)2 b)3 c)5
I suspect you want to know this for reasons that are not good and may be illegal.
I think the answer to that would be 2. Alpha hydrogen refers to a hydrogen atom that is attached to an alpha carbon. You can go to http://en.wikipedia.org/wiki/Alpha_and_beta_carbon and http://en.wikipedia.org/wiki/Phenylacetone for all the information you need.