Identify the most stable carbocation from the following:

Which of the following is the most stable carbanion?

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 $CH_3^{+}$

The correct stability order of the following carbocations is:
$I$. $H_2C^+-CH=CH-CH_3$
$II$. $H_2C^+-CH=CH-BMe_2$
$III$. $H_2C^+-CH=CH-NMe_2$
$IV$. $H_2C^+-CH=CH-OMe$

In the following carbocation,the $H$ or $CH_3$ group that is most likely to migrate to the positively charged carbon is:

Arrange the carbanions,$(CH_3)_3\overline{C}$,$\overline{C}Cl_3$,$(CH_3)_2\overline{C}H$,$C_6H_5\overline{C}H_2$ in order of their decreasing stability: