Question

Match the ions given in Column I with their nature given in Column II

	Column I		Column II
A		$\left(i\right)$	Stable due to resonance
B		$\left(ii\right)$	Destabilised due to inductive effect
C		$\left(iii\right)$	stabilised by hyperconjugation
D		$\left(iv\right)$	A secondary carbocation

Answer 1

(A)

The above carbocation is stabilised because of dispersal of positive charge via resonance. $-I$ effect ( i.e., electron withdrawing effect) of oxygen destabilize the carbocation.

Also, positively charged carbon ( carbocation) have three $\alpha$-hydrogens

( $C-H$ bonds next to $C^{+}$). So, it can also stabilized via hyperconjugation.

Hence, the correct match is:

$\left(A\right)\to \left(i\right),\left(ii\right),\left(iii\right)$.

(B)

Here, carbocation is destabilized by the negative $(-I)$ inductive effect of three fluorine atoms. It increases the positive charge density on carbocation center.

Hence, the correct match is:

$\left(B\right)\to \left(ii\right)$

(C)

Here, carbanion is destabilised due to the positive $(+I)$ inductive effect of three methyl groups. As methyl being an electron releasing group, increases the electron density on carbanion.

Hence, the correct match is:

$\left(C\right)\to \left(ii\right)$

(D)

Since positively charged carbon is directly attached with two other carbons, it is a secondary carbocation.

Here, secondary carbocation is stabilized by hyperconjugation via neighbouring
$C-H$ bonds ( involving $\alpha$-hydrogens ).

Hence, the correct match is:

$\left(D\right)\to \left(iii\right),\left(iv\right)$

So, the correct matches can be represented as:

$\left(A\right)\to \left(i\right),\left(ii\right),\left(iii\right)$,$\left(B\right)\to \left(ii\right)$,$\left(C\right)\to \left(ii\right)$,$\left(D\right)\to \left(iii\right),\left(iv\right)$