Mechanisms of vinyl chloride reactions

Steps:

• Identify Compound P as CH3CH=CHCl, a vinyl halide with a C=C bond.
• For KOH(aq): OH- acts as nucleophile, attacking the C-Cl bond for substitution (SN1-like due to sp2 carbon).
• For HBr: H+ adds to C=C (Markovnikov), followed by Br- addition, an electrophilic process.
• Match to options: substitution for KOH, addition for HBr.

Why C is correct:

• Vinyl halides undergo slow nucleophilic substitution with aq. bases like KOH; alkenes react with HBr via electrophilic addition per Markovnikov's rule.

Why the others are wrong:

• A: KOH reaction is substitution, not addition, as Cl is replaced without involving C=C.
• B: HBr addition is electrophilic, not free radical (no light/heat specified).
• D: HBr involves addition to C=C, not substitution on C-H.

Final answer: C