How will you distinguish the primary, secondary and tertiary alcohols by Victor Meyer’s method ?

Explanation

Victor Meyer's test:
(i) Alcohol is converted into alkyl iodide by treatment with `P//I_(2)`.
(ii) The alkyl iodide is then converted into nitro alkane by sivler nitrite `(AgNO_(2))`.
(iii) The nitro alkane is treated with nitrous acid `(HNO_(2))` and then with aqueous KOH.
(iv) The `1^(@), 2^(@)` and `3^(@)` alcohols are identified from the colour of the product.
(a) Primary alcohol:
`underset("Ethanol"1^(@))(CH_(3)-CH_(2)-OH) overset(P//I_(2)) to underset("Ethyl iodide") (CH_(3)CH_(2)I) overset(AgNO_(2)) to underset("Nitro ethane") (CH_(3)CH_(2)NO_(2)) overset(O=N -OH) to underset("Nitroxime")underset(NO_(2))underset(|)(CH_(3)C = NOH) overset(KOH) to underset("Potassium salt of nitrolic acid (Red)")underset(NO_(2))underset(|)(CH_(3)C=N-OK^(+))`
(b) Secondary alcohol:

( c)