Chapter 8, Problem 9A

Interpretation Introduction

Interpretation: The substances which are soluble in water needs to be identified.

Concept Introduction: The ability of the solute, to dissolve in solvent is known as solubility. Solubility rules are proposed for different ions, whether they are soluble or not. According to solubility rule, it will be confirm that given salt solution will form precipitate or remain aqueous.

Explanation of Solution

Reason for correct option:

According to the solubility rule, salts that contain Cl^-, Br −or I − ions are generally soluble in water. Also, the salts in which elements from group 1 are present, they are soluble in water.

Thus, potassium chloride − KCl is soluble in water as potassium is a group 1 element.

Now, all the salts containing phosphates are insoluble but if cations are Na⁺, K+ and NH₄⁺, they become soluble. Also, salts in which elements from group 1 are present, they are soluble in water.

Thus, sodium phosphate Na₃PO₄- is soluble in water.

The ammonium ion slats are generally soluble also, the salts of most sulphates are soluble thus, (NH₄)₂SO₄-is soluble in water.

Salts containing nitrate ion (NO₃^-) are generally soluble.

Thus, iron (III) nitrate Fe (NO₃)₃ is soluble

Conclusion

Reason for incorrect option:

Now, salts in which Cl - , Br − and I − ions are present are generally soluble except with the cations Ag+ , Pb²+ and (Hg₂)2+ .

Thus, AgCl is insoluble in water.

Carbonates are frequently insoluble. If the cations are from Group II thus, carbonates (are insoluble.

Thus, CaCO₃- is insoluble in water

According to the solubility rule, phosphates such as Ca₃(PO₄)₂ and Ag₃PO₄ are frequently insoluble.

Thus, chromium (III) Phosphate CrPO₄- is insoluble

The hydroxide salts are slightly soluble. But, if cations are from group 1, they are highly soluble.

Since, Pb is not a group 1 element thus, Pb(OH)₂ is slightly soluble in water.