The changes which take place when fats and oils are oxidised:

Complete the missing components/variables given as $x$ and $y$ in the following reactions:
$(a)$ $Zn(s) + H_2SO_4(aq) \longrightarrow ZnSO_4(x) + H_2(y)$
$(b)$ $CaCO_3(s) \xrightarrow{x} CaO(s) + CO_2(g)$

List two observations which you record while burning magnesium in air.

$(a)$ Define corrosion.
$(b)$ What is corrosion of iron called?
$(c)$ How will you recognise the corrosion of silver?

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.

Write true or false for the following statement: On heating the crystals of ferrous sulphate,the colour changes from green to grey.