JEE MainChemistrys Block Elements
Among the following nitrates, the number of nitrates that evolve a brown coloured gas on strong heating is ________. LiNO ₃, NaNO ₃, KNO ₃, RbNO ₃, Mg(NO ₃)₂, Ca(NO ₃)₂, Sr(NO ₃)₂, Ba(NO ₃)₂
Correct answer
5
Step-by-step solution
The thermal decomposition of s-block nitrates follows specific trends: Group 1 nitrates (except Lithium) decompose on heating to give the corresponding metal nitrite and oxygen gas (which is colourless). 2 MNO ₃ 2 MNO ₂ + O ₂ (where M = Na , K , Rb ) Group 2 nitrates and Lithium nitrate (due to its anomalous behaviour and diagonal relationship with Magnesium) decompose to give the corresponding metal oxide, nitrogen dioxide gas, and oxygen gas. 4 LiNO ₃ 2 Li ₂ O + 4 NO ₂ + O ₂ 2 M(NO ₃)₂ 2 MO + 4 NO ₂ + O ₂ (where