What can be seen when a strip of copper metal is placed in a solution of silver nitrate?

Observe the following diagram and answer the questions that follow:
$(i)$ Identify the gases evolved at anode and cathode.
$(ii)$ Why are the amounts of gases collected in the two test tubes not of the same volume?
$(iii)$ What type of reaction is this?
$(iv)$ Why should we use salt water?

On heating blue coloured powder of copper $(II)$ nitrate in a boiling tube,copper oxide (black),oxygen gas and a brown gas $X$ is formed.
$(a)$ Write a balanced chemical equation of the reaction.
$(b)$ Identify the brown gas $X$ evolved.

What would you observe when zinc is added to a solution of iron $(II)$ sulphate? Write the chemical reaction that takes place.

What do you mean by a precipitation reaction? Explain by giving examples.

State whether the following statement is true or false:
On heating lead nitrate crystals, the emission of brown fumes occurs.