Take copper nitrate in a test tube and heat it over the flame.Now, Identify the following statements as True or False.

1. The colour of cupric nitrate is blue.
2. During this reaction, green fumes are observed.
3. It is a combination reaction.
4. The chemical equation is-$2\mathrm{Cu}{\left({\mathrm{NO}}_3\right)}_2\stackrel{\mathrm{Heat}}{\to }2\mathrm{CuO}+4{\mathrm{NO}}_2\uparrow +{\mathrm{O}}_2\uparrow$

Copper nitrate is an inorganic compound with a chemical formula, $\mathrm{Cu}{\left({\mathrm{NO}}_3\right)}_2$ and it is a blue crystalline solid. Cupric nitrate shares the same hue as hydrated copper sulphate in terms of colour. On heating, copper nitrate, as seen, breaks down into two gases and a solid. One gas has colour, whilst the other cannot be seen with the unaided eye.

When it is heated in a test tube, the reaction that takes place is-

$2\mathrm{Cu}{\left({\mathrm{NO}}_3\right)}_2\stackrel{\mathrm{Heat}}{\to }2\mathrm{CuO}+4{\mathrm{NO}}_2\uparrow +{\mathrm{O}}_2\uparrow$

Hence, reddish-brown fumes of nitrogen dioxide are observed.

In this reaction, as copper nitrate is decomposing into more than one product, it is a type of decomposition reaction.

Thus, statements 1 and 4 are TRUE while statements 2 and 3 are FALSE.

Hence, the correct option is C.