A gas occupies 2.0 L at 1.0 atm. If pressure is increased to 4.0 atm at constant temperature, the volume will be: MCQ with Answer and Explanation

Explanation:
Ammonia reacts with CO₂ to produce urea: 2NH₃ + CO₂ → NH₂COONH₄ → (NH₂)₂CO + H₂O. It is also used to make ammonium sulfate, ammonium nitrate, DAP, etc. Superphosphate is made by treating rock phosphate with sulfuric acid; no ammonia. Gypsum is CaSO₄·2H₂O. Potassium sulfate is K₂SO₄. Ammonia is a key intermediate in nitrogenous fertilizers.

Explanation:
C₂H₆ (ethane) follows the general formula CnH₂n+2 (n=2 gives C₂H₆), which is the formula for alkanes. Alkanes are saturated hydrocarbons with single bonds. Alkenes have CnH₂n (e.g., C₂H₄), alkynes CnH₂n-2 (e.g., C₂H₂), alcohols have –OH group. Ethane is a component of natural gas and is used to produce ethylene. Methane (CH₄) is the simplest alkane.

Explanation:
Soap (sodium carboxylate) reacts with Ca²⁺ and Mg²⁺ ions present in hard water to form an insoluble precipitate known as scum. This reduces lathering and wastage of soap. Synthetic detergents do not form scum because their calcium/magnesium salts are soluble.