Lithium compounds impart ........colour to the flame.

Explanation

To answer the question "Lithium compounds impart ........color to the flame," we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Element**: We are focusing on lithium, which is an alkali metal.

2. **Understand Flame Test**: When lithium compounds are heated, they undergo a flame test. This is a qualitative analysis technique used to identify the presence of certain metal ions based on the color of the flame produced.

...