Which of the following oxides is not expected to react with sodium hydroxide?

Which of the following carbonates of alkali metals has the least thermal stability?

Zinc $(II)$ ion on reaction with $NaOH$ first gives a white precipitate which dissolves in excess of $NaOH$ due to the formation of:

With an increase in atomic number,the melting point of alkali metals $...$

The correct order of electropositive nature of $Li$,$Na$ and $K$ is

Which of the following explains why sodium metal exhibits metallic luster?