The amount of energy released by the addition of an electron to the outermost shell of an atom in its isolated gaseous state is ……………

1. electronegativity
2. valency
3. electron affinity
4. ionisation potential

The unsaturated hydrocarbons undergo

1. substitution reaction
2. oxidation reaction
3. addition reaction
4. None of the above

When magnesium burns in air, the atoms of the metal reacts with the oxygen gas to produce magnesium oxide.

Which of the following is correct?

P. It is a combination reaction.

Q. It is a Redox reaction

R. It is a decomposition reaction

1. Only P
2. Only Q
3. Only R
4. Both Q and R

Which of the following is NOT correct about electro-refining of copper?

1. Cathode is pure copper rod and anode is impure copper block.
2. Cathode is impure copper block and anode is pure copper rod.
3. Electrolyte is copper sulphate solution, acidified with sulphuric acid.
4. Anode mud may contain silver and gold as insoluble impurities.