Assertion: Both grignard reagent and dialkyl cadmium react with acid chlorides to form tert-alcohols.
Reason: Grignard reagents are as reactive as dialkyl cadmium.

Options

A. a. If both assertion and Reason are true and the Reason is the correct explanation of the assertion.
B. b. If both assertion and Reason are true but the reason is not the correct explanation of the assertion
C. c. If assertion is true but reason is false
D. d. If both assertion and reason are false.

Explanation

To solve the question, we need to analyze the assertion and reason provided:

**Assertion**: Both Grignard reagent and dialkyl cadmium react with acid chlorides to form tert-alcohols.

**Reason**: Grignard reagents are as reactive as dialkyl cadmium.

### Step-by-Step Solution:

1. **Understanding Grignard Reagents**:
- Grignard reagents (R-MgX) are highly reactive organomagnesium compounds. They act as nucleophiles and can react with electrophiles, such as acid chlorides.

2. **Reaction of Grignard Reagents with Acid Chlorides**:
- When a Grignard reagent reacts with an acid chloride, the nucleophile (R-) attacks the electrophilic carbon of the carbonyl group (C=O) in the acid chloride.
- This results in the formation of a tetrahedral intermediate, which then leads to the formation of a ketone after the leaving group (Cl) is expelled.
- A second equivalent of the Grignard reagent can then attack the ketone, leading to the formation of a tertiary alcohol after workup (hydrolysis).

3. **Understanding Dialkyl Cadmium**:
- Dialkyl cadmium (R2Cd) is less reactive compared to Grignard reagents. It is formed by the reaction of two equivalents of Grignard reagents with cadmium chloride.

4. **Reaction of Dialkyl Cadmium with Acid Chlorides**:
- When dialkyl cadmium reacts with acid chlorides, it also acts as a nucleophile. However, due to its lower reactivity, it typically forms a ketone rather than a tertiary alcohol.
- The reaction proceeds similarly to that of Grignard reagents, but the final product is a ketone, not a tertiary alcohol.

5. **Evaluating the Assertion and Reason**:
- The assertion states that both Grignard reagents and dialkyl cadmium form tertiary alcohols when reacting with acid chlorides. This is **false** because only Grignard reagents do so; dialkyl cadmium forms ketones.
- The reason states that Grignard reagents are as reactive as dialkyl cadmium. This is also **false** because Grignard reagents are significantly more reactive than dialkyl cadmium.

### Conclusion:
- Both the assertion and reason are false. Therefore, the correct option is **D**: Both assertion and reason are false.