Hydrochloric acid is produced by the reaction of NaCl with:
A. Concentrated sulphuric acid
B. Nitric acid
C. Sodium hydroxide
D. Ammonia
Answer: Option A
Solution (By JKExamLibrary)
NaCl + H₂SO₄ (conc.) → NaHSO₄ + HCl↑, at low temperature. At high temperature, NaHSO₄ + NaCl → Na₂SO₄ + HCl. This is the laboratory preparation of HCl gas. Industrial production is by direct combination of H₂ and Cl₂. Nitric acid is an oxidizer and would produce chlorine. Sodium hydroxide gives salt and water (neutralization). Ammonia reacts with acid.
Explanation:
Terylene is a synthetic fiber belonging to the polyester family. Chemically, it is polyethylene terephthalate (PET), formed by the condensation polymerization of ethylene glycol and terephthalic acid. It is widely used in textiles, plastic bottles, and recording tapes.
Explanation:
Froth flotation separates sulfide ores from gangue based on their wetting properties. Sometimes, an ore contains multiple sulfides. A depressant (like NaCN) is added to selectively prevent one mineral (e.g., FeS2) from attaching to the froth, allowing only the desired mineral (e.g., PbS) to be separated.
Explanation:
Calcium (Ca) has a valency of +2, and the phosphate ion (PO₄) has a valency of -3. To balance the charges, we need three calcium ions and two phosphate ions, giving the formula Ca₃(PO₄)₂. This is determined by criss-crossing the valencies of the constituent ions.
No comments yet. Be the first to start the discussion!