1. The blue colour of indigo is destroyed by hydric nitrate. 2 2. Red fumes (N2O1) are given off when the acid, diluted, is poured over copper filings. 3. A brownish red ring is formed at the line of contact when hydric sulphate has been carefully poured over the hydric nitrate mixed with ferrous sulphate. 189. What is the difference between a nitrate and a nitrite? Jan. 1871-Jan. 1879-Jan. 1882. The difference in composition is that a nitrate contains 3 atoms of oxygen, while the nitrite only contains 2. The difference in their formation is that a nitrate is formed by the substitution of a metal for the hydrogen in hydric nitrate (HNO3), and a nitrite is formed by the substitution of a metal for the hydrogen in hydric nitrite (HNO2). 190. Calculate the percentage composition of salopetre from the formula KNO3 (K = 39, N = 14, O = 16). June 1879. 191. If 126 grains of nitric acid (hydric nitrate) were neutralised with ammonia gas, what weight and what properties would the new compound have? Jan. 1876. Ammonia gas combines with all hydrogen salts or acids. Thus it combines with hydric nitrate, as may be seen by the following equation : NH3 + HNO3 Ammonia. 17 Hydric nitrate. = : (NH4)NO3 80 Ammonic nitrate. Thus the new compound consists of white crystals of ammonic nitrate, which are very soluble in water, but deprived of all acid properties. When heated, it is resolved into water and laughing gas (N2O). As the ammonia gas combines with one molecule or 63 grains of hydric nitrate to form 1 molecule or 80 grains of ammonic nitrate, 2 × 63 or 126 grains of hydric nitrate will form 2 x 80 = 160 grains of ammonic nitrate. CHAPTER VIII. AMMONIA (NH ̧). (Trihydric nitride--Volatile alkali-Spirits of hartshorn.) Or 8.5 grammes of NH3 measure 11.2 litres. 8.5 grains of NH, measure 444 cubic inches. |