To identify the general structure formula for primary amines, let's break down the options provided:
a. RNH2: This notation signifies that an amine group (NH2) is attached to an alkyl group (R). Primary amines are characterized by this structure, where one alkyl group is bound to a nitrogen atom that also has two hydrogen atoms.
b. RCONH2: This represents an amide, not a primary amine. It indicates a carbonyl group (C=O) bonded to both an alkyl group (R) and an amine group (NH2).
c. RCOONHR: This structure is an ester with an amine substituent, not a primary amine. The ester (RCOO-R') is combined with an amine (NHR).
d. RNCOOR': This formula is neither a primary amine nor representative of any common simple organic class in typical introductory organic chemistry terms. It seems to be some sort of complex or incorrect notation for this context.
Based on these explanations, the correct option for the general structure formula of primary amines is:
a. RNH2
