Which give coloured carbonate precipitate?

Assertion : Out of $$\mathrm{CrO}_3$$ and $$\mathrm{Al}_2 \mathrm{O}_3, \mathrm{CrO}_3$$ having lower melting point than $$\mathrm{Al}_2 \mathrm{O}_3$$.

Reason : Oxidation state of $$\mathrm{Cr}$$ in $$\mathrm{CrO}_3$$ is high.

Assertion : $$\mathrm{S}_2 \mathrm{O}_7^{2-}$$ and $$\mathrm{Cr}_2 \mathrm{O}_7^{2-}$$ both exist.

Reason : Both have same valence electrons.

Assertion : $$\mathrm{Yb}^{2+}$$ is more stable in compare to $$\mathrm{Gd}^{+2}$$.

Reason : The electronic configuration of GD is $$[\mathrm{Xe}] 4 f^7 5 d^2 6 s^2$$.