Which of the following is nott true?

Options

A. Allalkali metal carbonates are remarkable stable up to`1000^(@)C` above which they first melt and then eventually decompose into oxides.
B. The thermal stability of alkali metal carbonates increases as as we mpove down the group.
C. The aqueous solution of alkali metals carbonates are mild alkalies.
D. None of these.

Answer

A

Explanation

`Li_(2)CO_(3)` is considerable less stable and decomposes more readily. Lithium carbonate is not so stable to heat because `Li^(+)` being very small in size polarizes a large `CO_(3)^(2-)` ion leading to the formation of more stable `Li_(2)O` and `CO_(2)`-
`Li_(2)CO_(3)overset(Delta)toLi_(2)O+CO_(2)`
(2). As the electropositive character increases down the grop, the thermal stability of carbonates increases.
(3). Carbonates undergo hydrolysis to form alkaline solution:
`CO_(3)^(2-)+2H-OHtoH_(2)CO_(3)+2OH^(-)`