Question

The major product [R] in the following sequence of reactions is:

• A.

  

• B.

  

• C.

  

• D.

  

Answer 1

The correct option is B

Hydrite shift:

1. A hydrogen atom in a carbocation may undergo a hydride shift to improve the stability of the intermediate structure.
2. Usually, it is seen in rearrangement reactions. Compounds can produce structural isomers by moving a hydrogen atom from one carbon to another.

The correct answer is:(b)

• Zaitsev's rule, Saytzev's rule, and Z-rule are all variations of Saytzeff's rule. Alexander Zaitsev, a Russian chemist, studied various elimination reactions and discovered a general pattern in the resulting alkenes.
• Based on this analysis, Zaitsev concluded that stable alkenes are formed when hydrogen is removed from -carbon with a low number of hydrogen substituents.
• Saytzeff's Rule enters the picture during elimination reactions.
• The most substituted product is the most stable and preferred.
• This rule only applies to the regiochemistry of the elimination reaction and does not generalize about the product stereochemistry.

(b)

• Explanation: The by-product of a chemical reaction that is generated in the highest quantity of ${\mathrm{HgSO}}_4/{\mathrm{H}}_2{\mathrm{SO}}_4$.
• ${\mathrm{NaBH}}_4$ both break triple bonds into ketone, which is then reduced by transforming them into alcohol.
• In organic chemistry, reduction refers to the addition of hydrogen to a molecule or the removal of electronegative atoms from the molecule, such as oxygen or halogen.
• Diagram:

The explanation for the incorrect options:

(a)

• Explanation: The by-product of a chemical reaction that is generated in the highest quantity.
• ${\mathrm{NaBH}}_4$ both break single bonds into ketone, which is then reduced by transforming them into alcohol.
• A solvent protonates the oxygen in the alkoxide. Water, ethanol, and methanol are all acceptable solvents. These two processes happen at the same time.
• Diagram:

(c)

• Explanation: A solvent protonates the oxygen in the alkoxide. Water, ethanol, and methanol are all acceptable solvents. These two processes happen at the same time.
• ${\mathrm{NaBH}}_4$ both break double bonds into ketone, which is then reduced by transforming them into alcohol.
• Diagram:

(d)

• Explanation: The by-product of a chemical reaction that is generated in the highest quantity. $\mathrm{CH}$resonance is taking place.
  It is more stable.
• Diagram:

The correct options are (b)