Question

Name a metal nitrate which on heating is changed into metal oxide.

Answer 1

Hint: We know that the metals nitrates generally decompose on heating to give metal oxides, oxygen as well as nitrogen dioxide having brown fumes. The metal combines with nitrate and forms metal nitrates. All the metal nitrates won’t produce respective metal and on heating.

Complete answer:
As we know, metal nitrates on heating generally result in the formation of metal oxides, oxygen, and brown fumed nitrogen oxide. But due to differences in the size and other chemical properties, not all members of the group behave the same. In the given question, Lithium possesses some anomalous properties which are very different from other members of the group due to its small size and greater polarizing power. So, when lithium nitrate is heated, it results in lithium oxide.
When sodium nitrate is heated it forms nitrogen oxides which can cause fire hazards as it decomposes explosively and is a strong oxidizing agent. The magnesium nitrate when heated, decomposes to give magnesium oxide and nitrogen dioxide and liberates half oxygen. Few metal nitrates undergo decomposition on heating and form metal oxide. Metal oxides on heating their metal nitrate compounds. Rather, they give respective nitrites. For instance: calcium nitrate when heated, it decomposes to form the corresponding nitrite and give an oxygen molecule. A metal nitrate which on heating is changed into metal oxide is calcium nitrate.

Note:
Remember that the trivalent metal oxides like aluminum nitrate decompose and form aluminium oxide, nitrogen dioxide and oxygen as the products on heating. But alkali metals nitrates behave differently upon heating, releasing colorless and odorless gas due to their size difference.