Chapter 6, Problem 55E

Interpretation Introduction

Interpretation: The cation present in the unknown soluble ionic compound has to be predicted.

Concept introduction: When the cations and anions switch partners, they result in the formation of two new ionic compounds one of which is in the solid state. The solid product is an insoluble ionic compound called a precipitate.

The rules for salts to be soluble in water are as follows

1. 1. Most of the nitrate salts are soluble
2. 2. Salts containing the cation as alkali metal such as sodium, magnesium, rubidium etc and ammonium are said to be water soluble.
3. 3. Salts of Bromide, Chloride and iodide are said to be water soluble except in case of cations such as silver, lead and mercury.
4. 4. Most of the sulphate salts are soluble except barium sulphate, mercury sulphate, lead sulphate and calcium sulphate.
5. 5. Most of the hydroxides are sparingly soluble except sodium hydroxide and potassium hydroxide.
6. 6. Most of the sulphide, carbonate, chromates and phosphates are less soluble except those include in the rule 2.