Choose the correct order of reactivity for dehydration of the given al...
As I give 3 degree carbonation
II give 2 degree and iii give 1 degree
Choose the correct order of reactivity for dehydration of the given al...
The correct order of reactivity for dehydration of alcohols using concentrated sulfuric acid is given in option 'A', which is 2-methylpropan-2-ol, 2-butanol, 1-butanol, and 2-methylpropan-2-ol.
In general, the reactivity of alcohols in dehydration reactions depends on the stability of the carbocation intermediate formed during the reaction. The more stable the carbocation, the faster the reaction will proceed.
Here is a detailed explanation of why option 'A' is the correct order of reactivity:
1. 2-methylpropan-2-ol:
- This alcohol is a tertiary alcohol, meaning the carbon atom bearing the hydroxyl group (OH) is attached to three other carbon atoms.
- Tertiary carbocations are more stable than secondary or primary carbocations due to the presence of more alkyl groups which can donate electron density to stabilize the positive charge.
- Therefore, 2-methylpropan-2-ol is the most reactive alcohol in this list.
2. 2-butanol:
- This alcohol is a secondary alcohol, meaning the carbon atom bearing the hydroxyl group is attached to two other carbon atoms.
- Secondary carbocations are less stable than tertiary carbocations but more stable than primary carbocations.
- Therefore, 2-butanol is less reactive than 2-methylpropan-2-ol but more reactive than the remaining alcohols in the list.
3. 1-butanol:
- This alcohol is a primary alcohol, meaning the carbon atom bearing the hydroxyl group is attached to only one other carbon atom.
- Primary carbocations are the least stable among the three types of carbocations.
- Therefore, 1-butanol is less reactive than both 2-methylpropan-2-ol and 2-butanol but more reactive than 2-methylpropan-2-ol.
4. 2-methylpropan-2-ol:
- This alcohol is also a tertiary alcohol, similar to the first alcohol in the list (2-methylpropan-2-ol).
- As explained earlier, tertiary carbocations are more stable than secondary or primary carbocations.
- Therefore, 2-methylpropan-2-ol is the least reactive alcohol in this list.
In summary, the reactivity of alcohols in dehydration reactions using concentrated sulfuric acid follows the order: 2-methylpropan-2-ol > 2-butanol > 1-butanol > 2-methylpropan-2-ol.