Atomic Structure and Chemical Bonding — CHEMISTRY STD 9 — Question

Give reason for the following:
Molybdenum is used in the manufacture of ammonia.

Which test should be made before collecting hydrogen in a gas jar?

Identify the gases from the observations:
A colourless gas having a pungent and irritating smell, which turns blue litmus red. It gives dense white fumes when a glass rod dipped in ammonium hydroxide solution is held in it.

State the original colour of the following substance and colour of residue obtained after heating.
Copper carbonate

State the following:
The volume of a gas at 0 Kelvin

Describe all what you will observe when a picce of calcium is dropped into water.

State the modern periodic law.