In the purification of impure nickel by Mond's process, metal is purified by:
(1) Electrolytic reduction
(2) Vapour phase thermal decomposition
(3) Thermite reduction
(4) Carbon reduction
The reduction of an oxide by aluminium is called:
(1) Bayer's process
(2) Goldschmidt's aluminothermite process
(3) Hall's process
(4) van Arkel process
Which of the following statements is incorrect?
(1) calamine and siderite are carbonates
(2) argentite and cuprite are oxides
(3) zinc blende and pyrites are sulphides
(4) malachite and azurite are ores of copper
Match the column (I) and (II) and select the correct answer using the codes given below.
Column-I Column-II
(a) Argentite (1) Halide ore
(b) Cuprite (2) Carbonate ore
(c) Siderite (3) Oxide ore
(d) Carnallite (4) Sulphide ore
Codes :
a b c d a b c d
(A) 4 3 2 1 (B) 1 2 3 4
(C) 2 3 4 1 (D) 3 4 1 2
The correct statement among the following is:
1. | In the decomposition of oxide into oxygen and gaseous metal, entropy increases. |
2. | Decomposition of oxide is an endothermic change. |
3. | To make ∆G° negative, the temperature should be high enough so that T∆S° > ∆H°. |
4. | All of the above. |
Which does not represent the correct method?
(A) : Kroll
(B) : Mond
(C) : Van Arkel
(D) : Van Arkel
Main source of lead is galena (PbS). It is converted to Pb by:
(A)
(B)
(A) A (B) B
(C) both (D) none
For which of the following metals Bessemerisation process is important?
I : Fe, II : Cu, III : Al, IV : Silver :
(1) I, II
(2) II, III
(3) I, III
(4) all
The chemical processes in the production of steel from haematite ore involve:
(1) Reduction
(2) Oxidation
(3) Reduction followed by oxidation
(4) Oxidation followed by reduction
The chemical composition of "slag" formed during the smelting process in the extraction of copper is:
1. Cu2 + FeS
2. FeSiO3
3. CuFeS
4. Cu2S + FeO