Which of the following is not a use of noble gases?

Options

A. Argon is widely used for filling incandescent electric bulbs.
B. Neon is used in safety devices for protecting electrical instruments.
C. Radon is used in radiotherapy of cancer.
D. Helium is filled in tubes of cycles and scooters tyres.

Explanation

To determine which of the following is not a use of noble gases, we will analyze each option provided:

1. **Argon is widely used for filling incandescent electric bulbs.**
- **Analysis:** This statement is correct. Argon is an inert gas that is commonly used in incandescent bulbs to create an inert atmosphere, preventing the filament from oxidizing and prolonging its life.

2. **Neon is used in safety devices for protecting electrical instruments.**
- **Analysis:** This statement is also correct. Neon is used in high voltage indicators, switching gears, and various lighting applications, making it suitable for safety devices.

3. **Radon is used in radiotherapy in cancer.**
- **Analysis:** This statement is correct as well. Radon, being a radioactive noble gas, is utilized in certain types of radiotherapy for cancer treatment due to its radioactive properties.

4. **Helium is filled in tubes of cycles and scooters tires.**
- **Analysis:** This statement is incorrect. Helium is not typically used in the tires of bicycles and scooters; instead, nitrogen gas is commonly used for this purpose. Helium is more often used in applications like cooling superconducting magnets or in balloons.

Based on the analysis, the option that is not a use of noble gases is:

**Answer: D (Helium is filled in tubes of cycles and scooters tires.)**