The adduct of a compound (A) with isopropyl magnesium halide on hydrolysis gives a tertiary alcohol. The compound (A) is:

Options

A. An ester
B. A secondary alcohol
C. A primary alcohol
D. An aldehyde

Answer

To solve the problem, we need to identify the compound (A) that reacts with isopropyl magnesium halide (a Grignard reagent) to form a tertiary alcohol upon hydrolysis. Here’s a step-by-step solution:

### Step 1: Understand the Reaction
The reaction involves a Grignard reagent (isopropyl magnesium halide) reacting with a compound (A) to form an adduct. Upon hydrolysis, this adduct yields a tertiary alcohol.

**Hint:** Grignard reagents typically react with carbonyl compounds (aldehydes or ketones) to form alcohols.

### Step 2: Identify the Type of Compound (A)
Since the product is a tertiary alcohol, we need to consider that the Grignard reagent adds to a carbonyl compound. Tertiary alcohols are formed when a Grignard reagent reacts with a ketone or an aldehyde that has two alkyl groups already attached to the carbonyl carbon.

**Hint:** Tertiary alcohols require a carbonyl compound that can accommodate the addition of two alkyl groups.

### Step 3: Analyze the Grignard Reagent
The Grignard reagent in question is isopropyl magnesium halide, which has the structure (CH3)2CHO-. This means that it has two methyl groups and one isopropyl group, making it a good candidate for forming a tertiary alcohol when it reacts with a suitable carbonyl compound.

**Hint:** Isopropyl magnesium halide will add to a carbonyl compound to form a tertiary alcohol.

### Step 4: Determine the Carbonyl Compound
To form a tertiary alcohol, we need a carbonyl compound (A) that, when reacted with isopropyl magnesium halide, results in a tertiary alcohol. The simplest carbonyl compound that can achieve this is an aldehyde or a ketone.

- If we consider an aldehyde, it should be one that can provide the necessary carbon skeleton to form a tertiary alcohol after the reaction.
- A common aldehyde that can be used is acetaldehyde (CH3CHO). However, this would yield a secondary alcohol, which is not what we want.

**Hint:** Look for a carbonyl compound that allows for the formation of a tertiary alcohol.

### Step 5: Choose the Correct Compound (A)
The correct compound (A) must be a carbonyl compound that, when reacted with isopropyl magnesium halide, leads to a tertiary alcohol. The best candidate is formaldehyde (HCHO), which upon reaction with isopropyl magnesium halide will yield a tertiary alcohol.

**Hint:** Formaldehyde is the simplest aldehyde and can lead to the formation of a tertiary alcohol when reacted with a Grignard reagent.

### Step 6: Conclusion
Thus, the compound (A) that reacts with isopropyl magnesium halide to form a tertiary alcohol upon hydrolysis is formaldehyde (HCHO).

**Final Answer:** The compound (A) is formaldehyde (HCHO).