Daylight Hours: 9 hours, 11 minutes (-8m 42s). The Sun's altitude in Tromsoe tromsÃ¸. Today the horizontal line signifies the, horizon the vertical lines show the times of sunrise and. Sunset altitude and heading are displayed in the box on the. right
Hydrogen cyanide (HCN), sometimes called prussic acid, is an organic compound with the chemical formula HCN. It is a colorless, extremely poisonous and flammable liquid that boils slightly above room temperature, at 25.6 Â°C (78.1 Â°F).
Hydrogen chloride. Hydrogen chloride, (HCl), a compound of the elements hydrogen and chlorine, a gas at room temperature and pressure. A solution of the gas in water is called hydrochloric acid. 1  Hydrogen chloride may be formed by the direct combination of chlorine (Cl2) gas and hydrogen (H2) gas; the reaction is rapid at temperatures above 250Â° C (482Â° F). 2  Hydrochloric acid is prepared by dissolving gaseous hydrogen chloride in water.