Melting point：80 ℃（underer normal conditions）
Physical property：31% hydrochloric acid is a light yellow or colorless transparent, irritating liquid with a specific gravity of1.154（31%、20 ℃）,it soluble in water and produces a lot of heat.
Chemical property：：It has Strong acids's general properties, can react with alkali, various salts, metal oxides, and it can react with many active metal hydrochloric acid to release hydrogen gas.
Use：Hydrochloric acid is widely used in chemical, metallurgical, food, petroleum and other industrial sectors. Packaging, Storage and Tansportration: Because 31% hydrochloric acid is volatile, plastic barrels, cans, steel lined rubber tank trucks and other packages should be used for solid packaging. At the same time, they should be covered or flanged to seal, and the packaging container should be strictly anti-collision. Labor insurance articles should be well worn when handling hydrochloric acid.