Why metal oxide are bases without carrying hydroxide ions

Q.

What are the products when

a. Bases react with metal oxides.

b . Bases react with metal carbonates .

c. Bases react with metal hydroxides.

Q. Name
(a) a metallic hydroxide soluble in excess of NH₄OH.
(b) a metallic oxide soluble in excess of caustic soda solution.
(c) a strong alkali
(d) a weak alkali
(e) two coloured metal ions.
(f) two bases which are not alkalis but dissolve in strong alkalis.
(g) a coloured metallic oxide which dissolves in alkalis to yield colourless solutions.

Q. Few statements regarding the properties of bases are given below. Mark the correct statements
(i) Sodium hydroxide and potassium hydroxide are soluble in water.
(ii) Calcium hydroxide and magnesium hydroxide are partially soluble in water.
(iii) All metallic hydroxides react with acids to form their respective metallic salts.
(iv) Metallic oxides are acidic oxides hence they react with acids to form salts.

Q.

Name :

(a) a metallic hydroxide soluble in excess of $N{H}_{4}OH$.
(b) a metallic oxide soluble in excess of caustic soda solution. (c) a strong alkali.
(d) a weak alkali.
(e) two colourless metal ions.
(f) two coloured metal ions.
(g) a metal that evolves a gas which burns with a pop sound when boiled with alkali solutions.
(h) two bases which are not alkalis but dissolve in strong alkalis. (i) a coloured metallic oxide which dissolves in alkalis to yield colourless solutions.
(j) a colourless cation, not a representative element.

Q. Why all the metal oxide are base?