Which is the correct order of stability of the following three carbonium ions?
$(I)$ $CH_2 = CH - CH^+ - CH_3$
$(II)$ $CH_2 = C(CH_3) - CH_2^+$
$(III)$ $CH_3 - CH = CH - CH_2^+$

State True or False for the following statements:
$(i)$ $\mathop{C}\limits^{+}H_3$ and $CH_3\mathop{C}\limits^{+}H_2$ both are primary carbocations.
$(ii)$ $(CH_3)_3\mathop{C}\limits^{+}$ is a tertiary carbocation and all carbons are $sp^3$ hybridized.
$(iii)$ $\mathop{C}\limits^{+}H_3$ is trigonal planar.
$(iv)$ $CH_4$ is not trigonal planar.

The stability of the following carbocations follows the order:
$I. (CH_3)_3C^{\oplus}$
$II. (CH_3)_2C^{\oplus}(OCH_3)$
$III. CH_3CH_2CH_2CH_2^{\oplus}$
$IV. CH_3CH^{\oplus}CH_2CH_3$

Rank the bond dissociation energies of the bonds indicated with the arrows (from smallest to largest).

$A$ species having carbon with a sextet of electrons and which can act as an electrophile is called:

For the given reaction,the total number of possible products formed by the tertiary carbocation of $A$ is $.........$.