Methane on chlorination in sunlight gives: MCQ with Answer and Explanation

Explanation:
Gypsum (CaSO₄·2H₂O) is added to clinker to control the rapid reaction of tricalcium aluminate with water, which would otherwise cause flash (quick) setting. Gypsum slows down the hydration of C₃A, thus increasing the setting time and allowing workability. Without gypsum, cement would set almost immediately upon mixing with water, making placement impossible.

Explanation:
Reduction can be defined as loss of oxygen, gain of hydrogen, gain of electrons, or decrease in oxidation number. All are correct definitions.

Explanation:
Arsenic (As) is a metalloid, showing properties of both metals and non-metals. It is in group 15, period 4. Sodium and calcium are metals. Oxygen is a non-metal. Metalloids: B, Si, Ge, As, Sb, Te. They are semiconductors and form amphoteric oxides.