(a) Account for the acidity of alkynes.
(b) Explain the mechanism of sulphonation of benzene.
( c ) How will you convert the following :
(i) Ethyne to but-2-yne (ii) Propene to 2, 3-dimethylbutane (iii) Ethene to ethyne.

Explanation

( c ) (i) `underset("Ethyne")(HC-=CH)overset(2NaNH_(2))toNaC-=CNa overset(2CH_(3)Br)toCH_(3)underset("But-2-yne")(C-="CCH"(3))`
(ii) `underset("Propene")(CH_(3)CH=)CH_(2)overset(HBr)toCH_(3)underset(Br)underset(|)(C)HCH_(3)overset("Na, ether")underset("Wurtz reaction")to underset("2,3-Dimethyl butane")(CH_(3)underset(CH_(3))underset(|)(C)H-underset(CH_(3))underset(|)(C)H-CH_(3))`
(iii) `underset("Ethene")(CH_(2)=CH_(2))overset(Br_(2),"CCl"_(4))tounderset(Br)underset(|)(C)H_(2)-underset(Br)underset(|)(C)H_(2)overset("2 alc. KOH")tounderset("Ethyne")(HC-=CH)`