phenylhydrazine
noun
phe·nyl·hy·dra·zine
| \ ˌfen-ᵊl-ˈhī-drə-ˌzēn, ˌfēn-
\
\
Medical Definition of phenylhydrazine
: a toxic liquid nitrogen base C6H8N2 that reacts with aldehydes and ketones to form compounds useful in the identification of sugars