The formation of MgO from Mg and O₂ involves: MCQ with Answer and Explanation

Explanation:
Fossil fuels (coal, petroleum, natural gas) are formed from organic matter deposited in sedimentary layers, subjected to heat and pressure over geological timescales. They are non-renewable because their formation takes millions of years.

Explanation:
The element with atomic number 17 is Chlorine. Its electronic configuration is 2, 8, 7. It has 3 shells, so it is in Period 3. It has 7 valence electrons, so it belongs to Group 17 (10 + 7 = 17 in modern IUPAC notation) along with fluorine, bromine, and iodine.

Explanation:
Finely divided nickel is used as catalyst for hydrogenation of unsaturated oils to saturated fats. Platinum and palladium can also be used but are more expensive. The reaction occurs at about 150°C with H₂ gas. Nickel catalyst is prepared by reducing NiO with H₂. This is an important industrial process for making margarine and shortenings.