142 NON-METALLIC ELEMENTS IN BINARY COMPOUNDS
PREPARATION 7
HYDROCHLORIC ACID, HC1
Hydrogen chloride may be formed by direct synthesis from the
elements. Although this method has been used on a commercial
scale and yields a very pure product, it is not the one commonly
used. It is far more convenient to treat sodium chloride with
concentrated sulphuric acid. The volatile hydrogen chloride
escapes from the reaction mixture and the reaction goes to comple-
tion.
NaCl + H 2 SO 4 ^NaHSO4 + HC11
The gas is dissolved in water to give hydrochloric acid.
K
FIG. 18
Materials: sodium chloride, rock salt, NaCl, 117 grams
2F.W.
36 N sulphuric acid, 222 cc.
Apparatus: 2-liter round-bottom flask.
500-cc. Woulff bottle, 3-necked.
8-ounce wide-mouth bottle.
