Which gas is a mixture of carbon monoxide $(CO)$ and dihydrogen $(H_2)$?

Compound $X$ and aluminium are used to join railway tracks.
$(a)$ Identify the compound $X$.
$(b)$ Name the reaction.
$(c)$ Write down its chemical reaction.

Which metal is more reactive than magnesium $(Mg)$?

Which of the following ores is in the form of carbonate?

$(a)$ List two differences between calcination and roasting in tabular form.
$(b)$ Which method will you use to reduce the following? Explain by giving a suitable example.
$(i)$ Oxides of less reactive metals.
$(ii)$ Oxides of moderately reactive metals.
$(iii)$ Oxides of highly reactive metals.

Which of the following ores is in the form of oxide?