Explanation

• Ozone (O₃) is both beneficial and harmful depending on its location.
• In the Ozone Layer, it protects life by blocking UV rays.
• At ground level, it becomes a pollutant harmful to lungs and plants.
• Thus, it has a dual role in Earth’s atmosphere.

Last verified on 02-05-2026

Explanation

Composition of Air:

• Nitrogen → 78%
• Oxygen → 20.95%
• Argon → 0.93%
• Carbon dioxide → 0.04%
• Other gases → very small traces

Last verified on 30-04-2026

Explanation

• Sugar is the most soluble chemical in water.
• Sugar is made from sucrose.
• Sugar dissolves readily in water due to its polar nature.
• It forms hydrogen bonds with water molecules, increasing solubility.
• Used widely in food and beverages due to easy dissolution.

Last verified on 23-04-2026

Explanation

• Energy due to motion is called kinetic energy.
• Any moving object possesses this energy.
• It depends on mass and velocity of the body.
• Faster motion means more kinetic energy.

Last verified on 11-04-2026

Explanation

• Glass and pitch are examples of pseudo solids.
• Pseudo solid is a solid which possesses the property of liquids.
• Glass is a pseudo solid and in a very slow process, it flows like a liquid due to which the base of glass gets thicker than top.

Last verified on 02-04-2026

Explanation

• Nitrogen (N₂) makes up about 78% of Earth's atmosphere.
• It is a colorless, odorless, and inert gas, essential for life but not directly used in respiration.
  

Additional information:

Composition of Air – Approximate %:

• Nitrogen – 78%
• Oxygen – 21%
• Argon – 0.93%
• Carbon Dioxide – 0.04%
• Other trace gases (Neon, Helium, Methane, Krypton, etc.) – 0.03%

Last verified on 18-03-2026

Explanation

NOTE: Hydrogen is the lightest gas, but Helium is generally preferred. However, since "Helium" is not listed among your choices, the correct answer from the provided options is Hydrogen

• Helium is the lightest safe gas commonly used for:
• Party balloons
• Advertisement balloons
• Weather balloons

Common MCQ Confusion

• Hydrogen is actually the lightest gas overall, but it is highly flammable and can catch fire.
• Helium is slightly heavier than hydrogen but is non-flammable and safe, so it is used in balloons.

Last verified on 18-03-2026

Explanation

• Nitrogen (N2) makes up about 78% of the Earth's atmosphere.
• Making it the most abundant gas in the atmosphere.
• It is followed by oxygen (~21%), with other gases in much smaller amounts.

Last verified on 15-03-2026

Explanation

• Examples: Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn)
• Reason for Inactivity: Complete valence electron shell → chemically stable

Additional information:

• Rarely form compounds, mostly inert
• Used in lighting (Neon lights), welding (Argon), and as inert environments in laboratories

Last verified on 08-02-2026

Explanation

• Refrigerants are gases used in refrigerators to absorb heat and provide cooling.
• Freon (CFCs) and ammonia are commonly used in domestic and commercial refrigeration.
• They evaporate at low temperatures, absorbing heat from the fridge interior.
  

Last verified on 03-02-2026