Question

Propane is obtained from propene by which of the following methods?

• A. Wurtz reaction
• B. Dehydrogenation
• C. Frankland reaction
• D. Catalytic hydrogenation

Answer 1

Answer: (D)

(i) Wurtz reaction: It is method of preparation of alkane by reaction between alkyl halide and sodium. $2RX+2Na\stackrel{\text{ Ether }}{\to }R-R+2NaX$
(ii) Dehydrogenation: It is method of formation of alkene from alkane.
Hydrogen is removed from alkane during reaction.
(iii) Frankland reaction:
$\underset{\text{ alkyl halide }}{\mathrm{RX}}+Zn+XR\to \underset{\text{ alkane }}{R}+Zn{X}_2$
It is method of preparation of alkane from alkyl halide.
(iv) Catalytic hydrogenation: It is method of preparation of alkane from alkene.
Hydrogen is added during this reaction.
$C{H}_2=\underset{\text{ propene }}{\mathrm{CH}}-C{H}_3\underset{+H_{2}O}{\overset{200-300^{\circ }C}{\to }}$
$C{H}_3-\underset{\text{ propene }}{C{H}_2}-C{H}_3$