Exams › JEE Advanced › Chemistry
Consider the following reaction sequence: PhMgBr + (i) CH3CHO, (ii) NH4Cl -> X X + I2/NaOH -> Y + CHI3 Y + H+ -> Z Which of the following statements is incorrect?
- Compound X gives turbidity immediately in the Lucas test
- Conversion of X into Y proceeds via the haloform reaction
- Compound Z gives a positive sodium bicarbonate test
- CHCl3 on treatment with Ag/heat cannot give acetylene gas
Correct answer: Compound X gives turbidity immediately in the Lucas test
Solution
X = 1-phenylethanol (secondary alcohol), formed by Grignard addition of PhMgBr to acetaldehyde. Secondary alcohols give turbidity with Lucas reagent (ZnCl2/conc. HCl) only after 5 minutes, not immediately. Therefore statement A is incorrect.
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