The following compounds have been arranged in the order of their increasing thermal stabilities. Identify the correct order.
`K_(2)CO_(3)(I),Na_(2)CO_(3)(II),Rb_(2)CO_(3)(III),Li_(2)CO_(3)(IV)`

Options

A. `I lt II lt III lt IV`
B. `IV lt II lt III lt I`
C. `IV lt II lt I lt III`
D. `II lt IV lt III lt I`

Answer

3

Explanation

The thermal stabilites of carbonates increase down the group due to increase in metallic character `i.e.` electropositive character . Further bigger cation stabiliese bigger anion through crystal lattice energy effects.