Which among the following carbocations is the most reactive?

Arrange the following carbocations in the increasing order of stability with respect to their labels:

Label	Carbocation
$1$	$CH_3-CH^+-CH_3$
$2$	$CH_3^+$
$3$	$(CH_3)_3C^+$
$4$	$CH_3-CH_2^+$

Which of the following is the most stable carbocation?

Which of the following is the most stable carbocation?

What is the order of stability of the following carbocations?
$(X). CH_3 - \overset{\oplus}{C}H - CH_3$
$(Y). CH_3 - \overset{\oplus}{C}H - OCH_3$
$(Z). CH_3 - \overset{\oplus}{C}H - COCH_3$

Due to the presence of an unpaired electron,free radicals are .........