Noble gases are used in discharge tubes to give different colours. Reddish-orange glow is due to

Options

A. Ar
B. Ne
C. Xe
D. Kr

Explanation

To determine the cause of the reddish-orange glow in discharge tubes filled with noble gases, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Noble Gases**: Noble gases are a group of elements in Group 18 of the periodic table, including helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). They are known for their lack of reactivity due to having a complete valence shell.

**Hint**: Recall the properties of noble gases and their electron configurations.

2. **Discharge Tubes**: When an electric current passes through a gas in a discharge tube, it excites the gas atoms, causing them to emit light as they return to their ground state.

**Hint**: Consider how gases behave under electric discharge and the concept of excited states.

3. **Identifying the Gas**: The reddish-orange glow is specifically associated with a particular noble gas. In discharge tubes, the color emitted can vary depending on the gas used.

**Hint**: Think about which noble gas is commonly associated with reddish-orange light.

4. **Reddish-Orange Glow**: The reddish-orange glow in discharge tubes is primarily due to the presence of **neon (Ne)**. When neon gas is excited by an electric current, it emits light in the reddish-orange spectrum.

**Hint**: Remember that different noble gases emit different colors when excited, and focus on the specific color mentioned in the question.

5. **Conclusion**: Therefore, the reddish-orange glow in discharge tubes is due to the excitation of neon gas.

**Hint**: Summarize your findings by linking the specific color to the noble gas responsible for it.

### Final Answer:
The reddish-orange glow in discharge tubes is due to the excitation of **neon (Ne)** gas.