Choose the correct option:

(a) The metal other than aluminum, which has a strong affinity for oxygen is:

(A) Copper

(B) Magnesium

(C) Silver

(D) Gold

(b) A metallic oxide which cannot be reduced by normal reducing agents:

(A) Zinc oxide

(B) Magnesium oxide

(C) Copper (II) oxide

(D) Iron (III) oxide

Fill in the blanks:

(a) Usually …………… (sulphide/carbonate) ores are subjected to …………… (calcination/roasting) which is done in the absence of air

(b) Zinc blende is converted to oxide by …………… (roasting/calcination) process.

(c) Froth floatation process is generally used to concentrate …………… ores (sulphides/carbonate)

(a) Give the chemical names and formulae of the main ores of

(i) aluminium,

(ii) iron and

(iii) zinc.

(b) Which impurities are present in bauxite?

(c) What is red mud, how is it removed?

In order to obtain 1 tonne of aluminium, the following inputs are required: 4 tonnes of bauxite, 150 kg of sodium hydroxide and 600 kg of graphite. The aluminium compound in bauxite is aluminium oxide and the main impurity is iron (III) oxide. Aluminium is obtained by the electrolysis of aluminium oxide dissolved in cryolite.

(a) When bauxite is treated with sodium hydroxide solution, what happens to

(i) the aluminium oxide

(ii) the iron (III) oxide

(b) (i) Name the process used for the purification of bauxite.

(ii) Write the equation for the action of heat on aluminium hydroxide.

(c) (i) Write the formula of cryolite.

(ii) Write down the word which correctly completes the following sentence:

By dissolving aluminium oxide in cryolite a …………… (conducting/non-conducting) solution is produced.

(iii) Why is so much graphite required for the electrolytic process?

(iv) Write the equation for the reaction which takes place at the cathode

(v) What is the cathode made up of?