The most stable carbocation is:

The order of basicity is:

$\left(\mathrm{I}\right) \mathrm{Ph}-{\mathrm{CONH}}_2$

$\left(\mathrm{II}\right) \mathrm{Ph}-{\mathrm{NH}}_2$

$\left(\mathrm{III}\right) \mathrm{Ph}-{\mathrm{CH}}_2-{\mathrm{NH}}_2$

$\left(\mathrm{IV}\right) \mathrm{p}-{\mathrm{OCH}}_3\mathrm{Ph}-{\mathrm{NH}}_2$

The order of enol content in the following molecule is:

The stability order of the following anions:

The correct ${\mathrm{pK}}_{\mathrm{a}}$ order of the following acids is:

The preferred sites of protonation in the following compounds are: