Gases Analysis: Identifying the Incorrect Statement

This question asks us to identify the statement about different gases that is not correct. Let's examine each statement carefully concerning the properties and uses of Hydrogen, Helium, Oxygen, and Nitrogen.

Hydrogen Isotopes Statement Analysis

Statement 1: Hydrogen has 3 isotopes.

This statement is correct. Hydrogen exists in three naturally occurring isotopic forms:

• Protium (\(^1\)H): The most common isotope, containing one proton and no neutrons.
• Deuterium (\(^2\)H or D): Contains one proton and one neutron.
• Tritium (\(^3\)H or T): Contains one proton and two neutrons. Tritium is radioactive.

Helium Use in Electric Bulbs Statement Analysis

Statement 2: Helium is a commonly used gas in electric bulbs.

This statement is not correct. While Helium is an inert gas, it is not typically used in standard incandescent or even most common household lighting. Traditional incandescent bulbs often use Argon or Nitrogen gas. These gases help to slow down the evaporation of the tungsten filament, extending the bulb's life. Helium's low density and high thermal conductivity make it less suitable for this common application compared to Argon or Nitrogen. It finds use in specialized lighting like some types of fluorescent lamps or lasers, but not commonly in general electric bulbs.

Oxygen Use in Rocket Engines Statement Analysis

Statement 3: Oxygen is used to burn fuel in rocket engines in spacecraft.

This statement is correct. Rocket engines require a strong oxidizer to combust the fuel efficiently. Liquid Oxygen (LOX) is a widely used oxidizer in spacecraft and rocket propulsion systems. It provides the necessary oxygen for the rapid burning of rocket fuel, generating thrust.

Nitrogen Use in Food Packaging Statement Analysis

Statement 4: Nitrogen can be used in gaseous form to replace air in food packaging.

This statement is correct. Nitrogen gas (\(N_2\)) is often used in Modified Atmosphere Packaging (MAP) for food products. Being an inert gas, it displaces oxygen, which helps prevent oxidation, slows down the growth of aerobic microorganisms, and preserves the food's freshness, color, and texture. Replacing air with nitrogen significantly extends the shelf life of many packaged foods.

Conclusion on Gas Statements

Based on the analysis of each statement:

• Statement 1 (Hydrogen isotopes) is correct.
• Statement 2 (Helium in electric bulbs) is incorrect.
• Statement 3 (Oxygen in rocket engines) is correct.
• Statement 4 (Nitrogen in food packaging) is correct.

Therefore, the statement that is not correct is that Helium is commonly used in electric bulbs.