Question

1. A sample of hard water was found to loose its hardness on boiling. Name the type of hardness associated with this sample.

2. Write the name and formula of four minerals which cause permanent hardness of water. 

3. What are electron deficient hydrides? Whether they behave as Lewis acids or Lewis bases? Why?

Answer 1

1. Temporary hardness 

2. CaCl₂, MgCl₂, CaSO₄, MgSO₄

3. These are covalent hydrides having too few electrons for writing conventional Lewis structure. They act as Lewis acids because they can accept electrons, e.g. B₂H₆