Question

Double bonds can also act like Lewis bases, sharing their electrons with Lewis acids. Use curved arrows to show how each double bond below will react with HCl and draw the resulting carbocation.

Short answer

a)

b)

c)

Step-by-step solution

Lewis acid and bases

The species which accepts the lone pair of an electron is called Lewis acid.

The species that donates the lone pair of an electron is called Lewis base.

$\mathrm{\pi }$bonds also act as lewis bases because they share their electrons with lewis acids.

Reaction of ethene with HCI

In this reaction$\mathrm{\pi }$ bond of ethene attacks on data-custom-editor="chemistry" $\mathrm{HCI}$the molecule to form chloroethane. The reaction proceeds as follow;

Lewis acid and bases

The species which accepts the lone pair of an electron is called Lewis acid.

The species that donates the lone pair of an electron is called Lewis base.

$\mathrm{\pi }$bonds also act as lewis bases because they share their electrons with lewis acids.

Reaction of but-2-ene with HCI

In these reaction$\mathrm{\pi }$ bond of but-2-ene react with $\mathrm{HCI}$which result in the formation of 2-chlorobutane. The reaction mechanism is as follow;

Lewis acid and bases

The species which accepts the lone pair of an electron is called Lewis acid.

The species that donates the lone pair of an electron is called Lewis base.

$\mathrm{\pi }$bonds also act as lewis bases because they share their electrons with lewis acids.

Reaction of cyclohexene with HCI

In this reaction $\mathrm{HCI}$add across the double bond which results in the formation of the following compound;