Skip to content
dronacharya.ai
← IIT-JEE 2008 · Paper 2
ChemistrySingle correct+4 / -1Question 58 of 66

IIT-JEE 2008 · Paper 2, Chemistry question 58

Passage

Paragraph for Question Nos. 58 to 60

A tertiary alcohol H upon acid catalysed dehydration gives a product I. Ozonolysis of I leads to compounds J and K. Compound J upon reaction with KOH gives benzyl alcohol and a compound L, whereas K on reaction with KOH gives only M.

M = CHX3C(Ph)=CH−CO−Ph\ce{CH3C(Ph)=CH-CO-Ph} (dypnone; the CH₃ and the COPh group drawn on the same side of the C=C, Ph and H opposite).

M: 1,3-diphenylbut-2-en-1-one (dypnone), H₃C(Ph)C=CH-C(=O)Ph.

Compound H is formed by the reaction of

Choose one option
Answer and worked solution

Official answer: B

Work back from M. M (dypnone) is the self-aldol condensation product of acetophenone, so K is PhCOCHX3\ce{PhCOCH3}. J gives benzyl alcohol with KOH (a Cannizzaro reaction), so J is PhCHO.

Alkene I. Ozonolysis giving PhCHO and PhCOCHX3\ce{PhCOCH3} means I=PhCH=C(CHX3)Ph\mathbf I=\ce{PhCH=C(CH3)Ph}.

Alcohol H. The tertiary alcohol that dehydrates to I is PhCHX2C(OH)(CHX3)Ph\ce{PhCH2C(OH)(CH3)Ph}, made from acetophenone and benzylmagnesium bromide.

(B)

Topics:AlcoholsNucleophilic additionAlkenes
← Previous questionNext question →