Saved Bookmarks
| 1. |
Explain properties of hydrogen chloride. |
|
Answer» Solution :(i) Physical properties : It is a colourless and pungent smelling gas. It is easily liquefied to a colourless liquid (b.p.189 K) and freezes to a white crystalline solid (f.p. 159 K).It is HIGHLY soluble in water. Its aqueous solution is known as hydrochloric ACID. (ii) Chemical properties : In aqueous medium, it ionizes as `HCl(G) + H_(2)O (l) It reacts with `NH_3` and gives white fumes of `NH_(4)Cl` `NH_(3) + HCl to NH_(4)Cl` When three parts of CONCENTRATED HCl and one part of concentrated `HNO_3` are mixed, aqua regia is formed which is used for dissolving NOBLE metals, e.g., gold, platinum. `Au + 4H^(+) + NO_(3)^(-) + 4Cl^(-) to AuCl_(4)^(-) + NO + 2H_(2)O` `3Pt + 16H^(+) + 4NO_(3)^(-) + 18Cl^(-) to 3PtCl_(6)^(2-) + 4NO + 8H_(2)O` Hydrochloric acid decomposes salts of weaker acids, e.g., carbonates, hydrogen carbonates, sulphites, etc. `Na_(2)CO_(3) + 2HCl to 2NaCl + H_(2)O + CO_(2)` `NaHCO_(3) + HCl to NaCl + CO_(2) + H_(2)O` `Na_(2)SO_(3) + 2HCl to 2NaCl + H_(2)O + SO_(2)` |
|