Which is the most stable carbocation?

The hybridization of the positively charged carbon and the negatively charged carbon in the following structures are respectively:

Choose the most reasonable reaction intermediate for the following reaction.

$2-$chloropentane on halogenation with chlorine gives $2,3-$dichloropentane. What will be the structure of the free radical species formed in the reaction?

Which of the following is the most stable carbocation?

Arrange the following in decreasing order of stability.
$(i)$ $CH_3^{\bullet}$,$(CH_3)_3C^{\bullet}$,$(CH_3)_2CH^{\bullet}$ and $CH_3CH_2^{\bullet}$
$(ii)$ $CH_3CH_2^{+}$,$(CH_3)_3C^{+}$,$(CH_3)_2CH^{+}$ and $CH_3^{+}$