Class 12 NEET Chemistry Aldehydes, Ketones And Carboxylic Acids Part 2

Concept:The reaction sequence is the haloform reaction, where a methyl ketone reacts with halogen in base to give a sodium salt of a carboxylic acid (P) and a haloform (Q).Explanation:Step 1: In the haloform reaction, a compound containing the $CH_3CO-$ group reacts with $NaOX$ (or $X_2$ + base) to produce P (e.g., $RCOONa$) and Q (e.g., $CHCl_3$ or $CHI_3$).Step 2: When P is acidified, it forms the corresponding carboxylic acid ($RCOOH$).Step 3: Q, especially chloroform ($CHCl_3$), slowly oxidizes to phosgene ($COCl_2$) on exposure to air and light, which is a highly poisonous gas.Step 4: Option A is false because P is a salt, not a carbonyl compound, and Q is a haloform, not a carbonyl.Step 5: Option B is false because Q is a haloform, not a primary alcohol.Step 6: Option C is false because P and Q need not be aromatic; they can be aliphatic.Step 7: Only option D correctly describes the chemical properties of P and Q in this sequence.Answer:The correct option is D.