The relative order of reactivity of \(1^o , 2^o, 3^o\) alcohol towards dehydration is :

\(3^o > 2^o > 1^o\)

The relative order of reactivity of primary (\(1^\circ\)), secondary (\(2^\circ\)), and tertiary (\(3^\circ\)) alcohols towards dehydration is as follows: (4) \(3^\circ > 2^\circ > 1^\circ\)

Tertiary alcohols (\(3^\circ\)) are the most reactive towards dehydration, followed by secondary alcohols (\(2^\circ\)), and then primary alcohols (\(1^\circ\)). This is because the stability of the carbocation intermediate formed during the dehydration reaction increases with the degree of substitution of the carbon atom bearing the -OH group. Tertiary carbocations are the most stable, followed by secondary, and then primary carbocations. Therefore, tertiary alcohols undergo dehydration more readily than secondary and primary alcohols.