Explanation

In HNO₃ (nitric acid):

Hydrogen (H) = +1

Oxygen (O) = -2 (×3 = -6)

Let nitrogen = x

So, +1 + x + (−6) = 0

⇒ x = +5

Nitrogen has an oxidation state of +5 in HNO₃.

Explanation

Fe3O4 occurs as a mineral with a chemical name Iron (II, III) oxide.

It is also known as Magnetite or Magnetic oxide.

Explanation

Ozone (O₃) is a triatomic molecule of oxygen, not a noble (rare) gas.

Radon, Xenon, and Krypton are all noble gases found in Group 18 of the periodic table.

Explanation

Diamond is a non-metal with a high-density.

Graphite: A non-metal but has a lower density (~2.2 g/cm³).

Hydrogen: The lightest element with very low density (~0.000089 g/cm³).

Helium: Also very low density (~0.00018 g/cm³).

Diamond: A non-metal form of carbon with high density (~3.5 g/cm³).

Iron: A metal, so not a valid choice for a non-metal category.

Explanation

Sulfuric acid is a mineral acid composed of the elements sulfur, oxygen and hydrogen.

It is a colorless, odorless and viscous liquid that is miscible with water.

Explanation

Nitrogen dioxide (NO₂) and Sulphur dioxide (SO₂) dissolve in rainwater to form nitric acid and sulphuric acid, causing acid rain.

These gases are mainly released from burning fossil fuels.

Explanation

Surface area – Greater surface area increases the rate of evaporation.

Wind speed – Higher wind speed removes water vapor quickly, enhancing evaporation.

Explanation

Talcum powder is made from soap-stone (talc).

It is a soft mineral composed of magnesium, silicon, and oxygen.

It is widely used in cosmetics, baby powder, and industrial applications for its moisture-absorbing and friction-reducing properties.

Explanation

Explanation

• An Exothermic Reaction is a chemical reaction that releases or gives off heat, often accompanied by light, sound, or other forms of energy.
• This type of reaction involves a decrease in the system's energy, which is released into the surroundings as heat.