This question asks about methods of steam generation, the cleaning of magnesium, the identification of liquid M and the formation of oxygen gas.

Here are the solutions to the questions:

c) State two other ways of generating steam

1. Boiling water using an electric heater or gas burner.
2. Using a boiler in a thermal power plant, often fueled by coal, natural gas, or nuclear energy.

f) Why was magnesium used first cleaned with steel wool?
Magnesium is cleaned with steel wool to remove the layer of magnesium oxide ($\text{MgO}$) that forms on its surface when exposed to air. This oxide layer is unreactive and would prevent the magnesium from reacting properly.

Q4) the diagram below show a set up of apparatus used to prepare Oxygen over burning candle.

a) Identify liquid M
Liquid M is water ($\text{H}_2\text{O}$). It reacts with sodium peroxide to produce oxygen gas.

b) Write an equation:

i) For formation of Oxygen gas using hydrogen peroxide

$$2\text{H}_2\text{O}_2(aq) \to 2\text{H}_2\text{O}(l) + \text{O}_2(g)$$

ii) For formation of Oxygen gas using Potassium Manganate (VII)

$$2\text{KMnO}_4(s) \xrightarrow{\Delta} \text{K}_2\text{MnO}_4(s) + \text{MnO}_2(s) + \text{O}_2(g)$$

c) The pH of the solution in flask H was found to be less than 7.
❌ Incorrect.
Assuming "flask H" refers to the reaction flask where sodium peroxide reacts with water, the products are sodium hydroxide ($\text{NaOH}$) and oxygen gas. Sodium hydroxide is a strong base, which means the solution in the flask would be alkaline with a pH greater than 7.