Assertion (A): `Na_(2)CO_(3)` and `Li_(2)CO_(3)` are thermally stable.
Reason (R ): Both the carbonates are salts of large cations and large anions.

Options

A. If both (A) and (R ) are correct and (R ) is the correct explanation of (A).
B. If both (A) and (R ) are correct, but (R ) is not the correct explanation of (A).
C. If (A) is correct, but (R ) is incorrect.
D. If (A) is incorrect, but (R ) is correct.

Answer

D

Explanation

Correct reason: `Na_(2)CO_(3)` is thermally stable, but `Li_(2)CO_(3)` decomposes on heating.
`Li_(2)CO_(3)overset(Delta)rarr Li_(2)O+CO_(2)`
Correct reason: `Na_(2)CO_(3)` is thermally stable as large cation, `Na^(o+)`, form a stable compound with larger anion `CO_(3)^(2-)`, whereas `Li_(2)CO_(3)` is unstable as it is a salt of small `Li^(o+)` ion and larger `CO_(3)^(2-)` ion.