Name the oxidising and reducing agent in the following reaction:
$CuO + H_{2} \longrightarrow Cu + H_{2}O$

$A$ metal $P$,when exposed to moist air for a longer period of time,loses its shiny brown surface and gains a green coat. Why has this happened? Identify the metal. Write the name and chemical formula of this green-coloured compound. List two ways to prevent this process.

Write the balanced chemical equations for the following reactions and identify the type of reaction in each case.
$(a)$ Chlorine gas is passed in an aqueous potassium iodide solution to form potassium chloride solution and solid iodine.
$(b)$ Ethanol is burnt in air to form carbon dioxide,water and releases heat.

If copper metal is heated over a flame, it develops a coating. What is the colour and composition of this coating?

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.
$(a)$ Identify the type of reaction.
$(b)$ What could be the $pH$ range of an aqueous solution of the gas $X$?

In the double displacement reaction between aqueous potassium iodide and aqueous lead nitrate,a yellow precipitate of lead iodide is formed. While performing the activity if lead nitrate is not available,which of the following can be used in place of lead nitrate?