The metallic oxide/s which cannot be reduced by normal reducing agents ?

1. Magnesium oxide
2. Copper (II) oxide
3. Zinc oxide
4. Iron (III) oxide

The amphoteric metallic oxide is :

1. Calcium oxide
2. Barium oxide
3. Zinc oxide
4. Copper (II) oxide

The following questions are relevant to the extraction of Aluminium :

(i) State the reason for addition of caustic alkali to bauxite ore during purification of bauxite.

(ii) Give a balanced chemical equation for the above reaction.

(iii) Along with cryolite and alumina, another substance is added to the electrolyte mixture. Name the substance and give one reason for the addition.

Match the properties and uses of alloys in List 1 with the appropriate answer from List 2.

List 1:

1. The alloy contains Cu and Zn, is hard and is used in decorative articles.
2. It is stronger than Aluminium, light and is used in making light tools.
3. It is lustrous, hard, corrosion resistant and used in surgical instruments.
4. Tin lowers the melting point of the alloy and is used for soldering purpose.
5. The alloy is hard, brittle, takes up polish and is used for making statues.

List 2 :

(A) Duralumin

(B) Brass

(C) Bronze

(D) Stainless steel

(E) Solder