The valency of carbon in CO₂ is: MCQ with Answer and Explanation

Explanation:
Methane (CH₄) is a potent greenhouse gas, absorbing infrared radiation. Oxygen and nitrogen are diatomic and do not absorb IR. Argon is a noble gas, inert. Greenhouse gases include CO₂, CH₄, N₂O, CFCs, H₂O vapor.

Explanation:
Covalent compounds consist of molecules held together by weak van der Waals forces, unlike the strong electrostatic forces in ionic lattices. Therefore, less heat energy is required to break these intermolecular forces, resulting in low melting and boiling points. Both statements are true and R correctly explains A.

Explanation:
Potassium (K) is an alkali metal placed at the very top of the reactivity series. It reacts violently with water and air, requiring storage in kerosene. Gold, silver, and copper are noble or less reactive metals placed at the bottom of the series, often found in the free state.