Question

Do all metals react with base? If not, then which metals react and why?

Answer 1

Hint: Metals show a variety of reactions based on their chemical nature. Metals are electron donating elements and therefore have an electropositive nature. Their reaction with acids or bases depends upon their own tendency to act as an acid or base.

Complete answer:
Metals are electropositive elements that are characterized by their physical properties of being lustrous, malleable and ductile. These are good conductors of heat and electricity and are generally hard in nature. Majority of the elements present in the periodic table are metallic in nature and occupy the left positions. Chemically metals have a tendency to lose their electrons and form cations.
Metals themselves are very weakly basic in nature and tend to react with acids, liberating hydrogen gas during the reaction. Metals form salts by transforming themselves into cations and combining with the anions present in the acids.
Metals being weakly basic (due to their electropositive nature) do not react with bases. But certain metals are amphoteric in nature and therefore react with bases to form complex salts (containing more than one type of cations) and liberation hydrogen gas. Zinc and aluminium are such amphoteric metals that react with strong bases like sodium or potassium hydroxide. The reactions can be written as follows:
 $ Zn + 2NaOH(aq) \to N{a_2}Zn{O_2} + {H_2}(g) \uparrow $
 $ 2Al + 2KOH(aq) \to 2KAl{O_2} + 3{H_2}(g) \uparrow $
Complex salts formed are Sodium zincate $ N{a_2}Zn{O_2} $ and Potassium aluminate $ KAl{O_2} $
Hence, not all metals react with bases, only amphoteric metals like zinc and aluminium react with bases.

Note:
An amphoteric element or compound is a chemical species that is capable of acting as an acid as well as a base and therefore reacts with both acids and bases. Zinc and aluminium react with both acids and bases are therefore called amphoteric metals.