Which of the following statement is not true?

Options

A. Flame is a zone of combustion of gaseous substances accompanied by heat and light.
B. Type of flame depends upon the amount of oxygen available.
C. Innermost zone of a flame is the hottest part of zone.
D. Blue zone indicates complete combustion of fuel.

Explanation

To determine which statement is not true, we will analyze the statements related to flames and combustion.

### Step-by-Step Solution:

1. **Understanding the Flame**:
- A flame is defined as a zone of combustion of gases and substances that produces heat and light.
- This statement is true because combustion indeed produces heat and light.

2. **Oxygen and Flame Type**:
- The type of flame depends on the amount of oxygen available.
- This statement is also true. The availability of oxygen influences whether the combustion is complete or incomplete, affecting the flame's characteristics.

3. **Zones of Flame**:
- Flames consist of different zones: the outer zone, the middle zone, and the inner zone.
- The outer zone is the hottest and is blue in color, indicating complete combustion.
- The middle zone is moderately hot and yellow in color, indicating partial combustion.
- The inner zone is the least hot and is black in color, indicating the presence of unburnt particles.

4. **Identifying the False Statement**:
- The inner zone is described as the hottest part of the flame, which is incorrect. It is actually the least hot zone.
- Therefore, the statement claiming that the inner zone is the hottest part of the flame is not true.

### Conclusion:
The statement that is not true is that "the inner zone is the hottest part of the flame."