- No. iv. What are complex salts?
Answer. Complex salts on dissociation provides a simple cation and a complex anion or vice versa. Only the simple ions yield the characteristics test for cation or anion. For example:
Potassium ferrocyanide K4 [Fe (CN) 6) gives on ionization a simple cation K+ and complex anion [Fe (CN) 6]4-
- No. v. How double salt is prepared?
Answer. Double salt is formed when aqueous solution of two normal salts is crystallized. The individual salt components retain their properties. The anions and cations give their respective tests. Mohr’s salt FeSO4 (NH4)2SO4 6H2O; Potash Alum K2SO4. Al2 (SO4) 3 24H2O are examples of double salts.
- No. vi. Which acids are mineral acid?
Answer. Hydrochloric acid (HCI), sulphuric acid (H2SO4) and nitric acid (H2SO4) are called mineral acids.
No.2. Define a base and explain: all alkalis are bases, but all bases are not alkalis.
Answer. Base is defined as a compound that dissolves in water to give OH~ ions. Alkali is defined as a compound that is soluble in water and gives large number of QH~ ions. Strong bases are called alkalis like NaOH, KOH. But A1 (OH)3 is not alkali because it is weak base and in aqueous solution forms relatively small amount of OH~ ions. Some bases are soluble in water but some are not. For example NaOH is soluble in water but Be (OH) 2 is not .Hence, bases which completely ionize in water are called alkalis.