Classify the following as primary,secondary,and tertiary alcohols:
$(i)$ $CH_3-C(CH_3)_2-CH_2OH$
$(ii)$ $CH_2=CH-CH_2OH$
$(iii)$ $CH_3-CH_2-CH_2-OH$
$(iv)$ $C_6H_5-CH(OH)-CH_3$
$(v)$ $C_6H_5-CH_2-CH(OH)-CH_3$
$(vi)$ $C_6H_5-CH=CH-C(OH)(CH_3)_2$

(N/A) To classify alcohols,we look at the carbon atom to which the $-OH$ group is attached:
$1$. Primary $(1^{\circ})$ alcohol: The $-OH$ group is attached to a carbon atom bonded to only one other carbon atom.
- $(i)$ $CH_3-C(CH_3)_2-CH_2OH$: The $-CH_2OH$ carbon is attached to one quaternary carbon.
- $(ii)$ $CH_2=CH-CH_2OH$: The $-CH_2OH$ carbon is attached to one $sp^2$ hybridized carbon.
- $(iii)$ $CH_3-CH_2-CH_2-OH$: The $-CH_2OH$ carbon is attached to one primary carbon.
$2$. Secondary $(2^{\circ})$ alcohol: The $-OH$ group is attached to a carbon atom bonded to two other carbon atoms.
- $(iv)$ $C_6H_5-CH(OH)-CH_3$: The $-CH(OH)-$ carbon is attached to a phenyl group and a methyl group.
- $(v)$ $C_6H_5-CH_2-CH(OH)-CH_3$: The $-CH(OH)-$ carbon is attached to a $-CH_2C_6H_5$ group and a methyl group.
$3$. Tertiary $(3^{\circ})$ alcohol: The $-OH$ group is attached to a carbon atom bonded to three other carbon atoms.
- $(vi)$ $C_6H_5-CH=CH-C(OH)(CH_3)_2$: The $-C(OH)-$ carbon is attached to two methyl groups and one alkenyl group.