Which of the following is used as a drying agent (dehydrating agent)? MCQ with Answer and Explanation

Explanation:
Magnesium oxide (MgO) is a basic oxide because it reacts with acids to form salt and water, e.g., MgO + 2HCl → MgCl₂ + H₂O. However, Reason is false: Metals generally form basic oxides, not acidic oxides. Non-metals form acidic oxides (e.g., SO₂, CO₂). Some metals like Al, Zn form amphoteric oxides. So A is true, R false. Exam tip: Metal oxides are usually basic; non-metal oxides are acidic.

Explanation:
Methyl orange is red in acidic (pH4.4). So yellow indicates pH above 4.4; could be neutral or basic.

Explanation:
Green manure refers to crops (like sunn hemp or dhaincha) that are grown specifically to be plowed back into the soil while they are still green. This decomposing plant material enriches the soil with organic matter, nitrogen, and other nutrients, improving soil structure and fertility.