A waxy crystalline solid `(A)` with a garlic odour is obtained by burning white `P` in a stream of air and nitrogen. What is A

Explanation

To solve the question, we need to identify the waxy crystalline solid `(A)` that has a garlic odor and is produced by burning white phosphorus in a stream of air and nitrogen.

### Step-by-Step Solution:

1. **Identify the Substance**: The question mentions a waxy crystalline solid `(A)` with a garlic odor. This hints at a phosphorus compound, as phosphorus is known for having a garlic-like smell.

2. **Understand the Reaction**: The question states that `(A)` is obtained by burning white phosphorus. White phosphorus is represented as `P4`. When white phosphorus is burned in the presence of air (which contains oxygen), it reacts with oxygen to form phosphorus oxides.

3. **Determine the Oxide Formed**: When white phosphorus is burned in a limited supply of oxygen (as in the presence of air), it primarily forms diphosphorus trioxide, which has the formula `P4O6`. This compound is known to have a waxy appearance and is indeed associated with a garlic-like odor.

4. **Conclude the Identity of `(A)`**: Based on the reaction of white phosphorus with oxygen, the waxy crystalline solid `(A)` that is formed is `P4O6`.

### Final Answer:
The waxy crystalline solid `(A)` is **P4O6** (diphosphorus trioxide).

---