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The intermediate stages in the convertsi...

The intermediate stages in the convertsion
`(CH_(3))_(2)-underset(OH)underset(|)C-underset(OH)underset(|)C-(CH_(3))_(2)underset(Delta)overset(dil. H_(2)SO_(4))rarrCH_(3)COC (CH_(3))_(2)` are

A

`(CH_(3))_(2)-underset(OH)underset(|)C-underset(o+)underset(OH_(2)^(-))underset(|)C(CH_(3))_(2)`

B

`(CH_(3))_(2)-underset(OH)underset(|)C-overset(o+)C(CH_(3))_(2)`

C

`CH_(3)-underset(OH)underset(|)overset(o+)C-C(CH_(3))_(3)`

D

`CH_(3)-underset(o+)underset(OH)underset(||)C-C(CH_(3))_(3)`

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To solve the problem regarding the intermediate stages in the conversion of the given dihydroxy compound to the final product using dilute sulfuric acid, we will follow these steps: ### Step-by-Step Solution: 1. **Protonation of the Alcohol**: - When the dihydroxy compound is treated with dilute sulfuric acid (H₂SO₄), the first step involves the protonation of one of the hydroxyl (OH) groups. The lone pair of electrons on the oxygen atom of the OH group attacks a proton (H⁺) from the sulfuric acid, forming an oxonium ion. - **Intermediate 1**: The structure now has a positive charge on the oxygen, forming an oxonium ion. 2. **Loss of Water**: - The oxonium ion is unstable, and one of the hydroxyl groups (now a water molecule) will leave, resulting in the formation of a carbocation. This step involves the departure of a water molecule (H₂O). - **Intermediate 2**: The structure now has a positively charged carbon atom (carbocation) where the water molecule was lost. 3. **Methyl Shift**: - The carbocation formed can undergo rearrangement through a methyl shift. One of the methyl groups from the neighboring carbon atom shifts to the positively charged carbon, stabilizing the carbocation. - **Intermediate 3**: The structure now has a new carbocation with an additional methyl group attached, resulting in a more stable tertiary carbocation. 4. **Formation of Double Bond**: - The final step involves the deprotonation of the hydroxyl group, where the lone pair of electrons on the oxygen atom forms a double bond with the positively charged carbon. This results in the formation of a carbonyl group (C=O). - **Intermediate 4**: The structure now has a carbonyl group, indicating the formation of a ketone. 5. **Final Product**: - The final product is a ketone, specifically the compound CH₃COC(CH₃)₂, which is formed after the rearrangement and stabilization of the intermediates. ### Summary of Intermediates: - **Intermediate 1**: Oxonium ion (protonated alcohol) - **Intermediate 2**: Carbocation (after loss of water) - **Intermediate 3**: More stable carbocation (after methyl shift) - **Intermediate 4**: Carbonyl compound (after formation of double bond)
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ALLEN-ALKENE, ALKANE & ALKYNE -EXERCISE-2
  1. Which of the following will increase the acidity of phenol ?

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  2. In the esterification of propanoic acid with methanol in the presence ...

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  3. The intermediate stages in the convertsion (CH(3))(2)-underset(OH)un...

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  4. An alcohol, on treatment with P+I(2) followed by the reaction of the...

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  5. Which one of the following will result in the formation of an ether?

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  6. The end products of the following sequence of reactions are

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  7. Which of the following compound on treatment with LiAlH(4) will give a...

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  8. Which of the following compounds is most susceptible to a nucleophilic...

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  9. Which of the following does not give lodoform reaction ?

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  10. Which of the following will undergo periodic oxidation?

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  11. overset(OH^(-))rarrA,A is :-

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  12. In the reaction sequence, [X] is ketone : [X] overset(KMnO(4)//OH^(-...

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  13. In the given reaction : (A) and (B) are :

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  14. In Cannizzaro reaction given below : 2PhCHO overset(: OH^(-)) to ...

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  15. Identify (Z) is the series given below. CH2 =CH2 overset(HBr)rarr (X...

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  16. Which of the following statements are correct ?

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  17. CH(3)-CHOoverset(veC CH)rarrCH(3)CH(OH)CH(2)CHO In the aldol condens...

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  18. When m-chlorobenzaldehyde is treated with 50% KOH solution, the produc...

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  19. The conversion : can be effected by using the reagent

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  20. Which of he following hydrogens will be most acidic?

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