Order of Reactivity in Dehydration Reaction of Alcohols

1. CH3CH(OH)CH2CN
2. CH3CH(OH)CH2CHO
3. CH3CH(OH)CH2C=OCH3
4. CH3CH(OH)CH2NO2

Explanation

Dehydration reaction of alcohols is a process in which water molecule is eliminated from the alcohol molecule to form an unsaturated compound. The order of reactivity in dehydration reaction depends on the stability of the carbocation intermediate formed during the reaction. The more stable the carbocation intermediate, the higher will be the reactivity of the alcohol.

1. CH3CH(OH)CH2CN - This alcohol is the most reactive in dehydration reaction due to the resonance stabilization of the carbocation intermediate formed during the reaction. The lone pair of electrons on the nitrogen atom can donate its electrons to the carbocation intermediate to form a resonance structure, which stabilizes the intermediate.

2. CH3CH(OH)CH2CHO - This alcohol is less reactive than the previous one due to the absence of resonance stabilization. However, the carbonyl group in the intermediate can stabilize the positive charge by delocalizing the electrons.

3. CH3CH(OH)CH2C=OCH3 - This alcohol is less reactive than the previous one due to the absence of resonance stabilization. The carbonyl group can stabilize the positive charge but not as effectively as in the previous alcohol.

4. CH3CH(OH)CH2NO2 - This alcohol is the least reactive in dehydration reaction due to the electron-withdrawing nature of the nitro group. The nitro group reduces the electron density on the carbon atom, making it less likely to lose a water molecule.

Conclusion

In conclusion, the order of reactivity in dehydration reaction of alcohols is determined by the stability of the carbocation intermediate formed during the reaction. The more stable the carbocation intermediate, the higher will be the reactivity of the alcohol.

Bro dehydration ke order ke liy aap alpha carbon ko carbo cation m convert kro fir uski stability dekhle. ok bro
mera answer h 4 > 2 > 3 >1 ( - m effect order
No2 > CN> aldehyde > ketone hota h )