On strongly heating copper nitrate, we get: (a) Copper metal (b) Cuprous oxide (c) Cupric oxide (d) Copper sulphate

Chemical decomposition, also known as chemical breakdown or analysis, is a process in which a compound is broken down into simpler substances or its constituent elements under the influence of heat, light, or other chemical agents. In the case of copper nitrate, when subjected to strong heating, it undergoes a thermal decomposition reaction. This type of decomposition is endothermic, meaning it requires heat to proceed.

During the heating process, the copper nitrate breaks down into copper oxides, nitrogen dioxide, and oxygen. The formula for this reaction can be expressed as : \[2Cu(NO_3)_2 \rightarrow 2CuO + 4NO_2 + O_2\].

This reaction is crucial to understand because it does not directly produce elemental copper or compounds such as copper sulphate. Instead, it predominantly yields cupric oxide as the copper-containing product. The evolution of gases like nitrogen dioxide is also a characteristic feature of the thermal decomposition of nitrates.

The oxidation state, or oxidation number, is a figure that represents the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom. In the example of copper nitrate undergoing heating, the copper transitions between different oxidation states. Copper can exhibit multiple oxidation states, but the most common are +1 and +2.

The +1 oxidation state corresponds to cuprous compounds, like cuprous oxide (Cu2O), whereas the +2 state corresponds to cupric compounds, such as cupric oxide (CuO). The nitrate in copper nitrate, being a potent oxidizer, tends to favor the formation of the higher oxidation state, which is cupric (+2) rather than cuprous (+1).

The inherent stability and common occurrence of the +2 oxidation state in environments where copper is combined with a high oxidation-state anion like nitrate guide the preference towards the formation of cupric oxide rather than cuprous oxide or elemental copper.

Cupric oxide, symbolized as CuO, is a black solid that forms upon the heating of copper nitrate. Its formation can be understood through the concept of oxidation states discussed earlier. When copper nitrate decomposes, the copper within the compound achieves a +2 oxidation state, leading to the creation of cupric oxide.

The reaction to form cupric oxide is a direct consequence of the chemical decomposition of copper nitrate. On strong heating, as mentioned, cupric oxide is produced along with other by-products. This specific type of copper oxide is significant in various applications, ranging from acting as a pigment in ceramics to its use in the creation of semiconductor devices.

The solid reasoned argument for the formation of CuO rather than Cu2O when strongly heating copper nitrate lies in the stability of the cupric (+2) oxidation state when associated with the nitrate anion. This explanation helps to clarify why, among the given options, cupric oxide is the correct choice for the product of this reaction.