Answer to Question #75593 in Inorganic Chemistry for Sakshi

Question

Name the factors that affect the thermal stability of alkali metal salts. Explain the stability trend observed in case of nitrates of these metals.

Answer 1

The thermal stability of a substance depends heavily on the structure of the substance which, in turn, is dependent on the bonds between atoms that hold that structure together.
Group 1 nitrates decompose to form products: MeNO2 + O2
Going down Groups 1, nitrates become more stable. Higher temperatures are needed to decompose them. Cations (positively charged ions) can affect anions such as NO3-. They can lower the energy needed to break a N–O bond.
This effect increases:
• the smaller the cation
• the greater the cation’s charge.
The small positive ions at the top of the Group polarise the nitrate more than the larger positive ions at the bottom.