Hydrargyrum is the Latin name of:

1. Gold
2. Silver
3. Mercury
4. Platinum

In Zn₃(PO₄)₂, the valency of Zn and Phosphate respectively is:

1. 3 and 2
2. 2 and 6
3. 4 and 6
4. 2 and 3

In C₂H₄, the valency of carbon is:

1. 2
2. 1
3. 4
4. 3

Which of the following represent the correct chemical formula of a compound :

1. NaSO₄
2. AlSO₄
3. NH₄PO₄
4. Ca₃N₂