JEE Main 2026 · 5 Apr · Shift 1 · Chemistry Q67

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ChemistrySingle correct+4 / -1Question 67 of 75

Consider compounds A, B and C with following structural formulae
A = $\ce{CH3-CH2-CH2-CH2-CH2-OH}$
B = $\ce{CH2=CH-CH2-CH2-CH3}$
C = $\ce{HO-CH2-CH2-CH(OH)-CH3}$
For the conversion of B from A, reagent (D) required is ________ and structural formula of product (E) obtained when C undergoes same reaction using excess reagent (D) is ________.

D: Conc.

\ce{H2SO4}

; E:

\ce{CH2=CH-CH(OH)CH3}

D: PCC; E:

\ce{HO-CH2-CH2-CH=CH2}

D: PCC; E:

\ce{CH2=CH-CH=CH2}

D: Conc.

\ce{H2SO4}

\ce{H3PO4}

; E:

\ce{CH2=CH-CH=CH2}

Answer and worked solution

Official answer: D

Reagent D. Pentan-1-ol to pent-1-ene is acid-catalysed dehydration. D is concentrated $\ce{H2SO4}$ (or $\ce{H3PO4}$ ) with heat. PCC would only oxidise the alcohol.

Product E. With excess acid, both OH groups of butane-1,3-diol, $\ce{HOCH2CH2CH(OH)CH3}$ , are eliminated. This gives buta-1,3-diene, $\ce{CH2=CH-CH=CH2}$ .

(D)

Topics:Alcohols Alkenes

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JEE Main 2026 · 5 Apr · Shift 1, Chemistry question 67