General Principles & Processes of Isolation Practice Questions - DPP for NEET

 Page 1


1. (a) The conversion of metal sulphide to metal oxide involves the
process of roasting (i.e., x is roasting).
The metal oxides can then be converted to impure metal by reduction.
Of the given choices in (a) and (b) the reduction process is that of
smelting. (i.e., ‘y’ is smelting)
The conversion of impure metal to pure metal involves a process of
purification. Thus it is electrolysis.
2. (b)
3. (c)
4. (b)
5. (a) Dolomite on calcination gives CaO, MgO which provides basic
lining in furnace.
6. (c) Zn being more reactive than Ag and Au, displaces them.
4Ag + 8NaCN + 2H
2
O + O
2
 4Na[Ag(CN)
2
] + 4NaOH
Sodium dicyanoargentate (I)
Soluble
Soluble cyanide compound can be treated with Zn to give metal by
displacement.
2Na[Ag(CN)
2
] + Zn   Na
2
[Zn(CN)
4
] + 2Ag?
7. (d) Decomposition of carbonates and hydrated oxides.
8. (c)
9. (b) Pig iron or cast iron contains 3 – 5% carbon and varying amounts
of Mn, Si, P and S which makes the iron hard and brittle.
10. (b) Cuprite is Cu
2
O and Argentite is .
11. (b) Cyanide process is for gold (I-D); floatation process - pine oil (II-
B); Electrolytic reduction - Al (III-C); Zone refining -Ge (IV-A).
12. (b) For a spontaneous reaction , ? Gº must be negative and it can be
possible only in this case when x < y.
13. (c) Fused alumina (Al
2
O
3
) is a bad conductor of electricity. Therefore,
Page 2


1. (a) The conversion of metal sulphide to metal oxide involves the
process of roasting (i.e., x is roasting).
The metal oxides can then be converted to impure metal by reduction.
Of the given choices in (a) and (b) the reduction process is that of
smelting. (i.e., ‘y’ is smelting)
The conversion of impure metal to pure metal involves a process of
purification. Thus it is electrolysis.
2. (b)
3. (c)
4. (b)
5. (a) Dolomite on calcination gives CaO, MgO which provides basic
lining in furnace.
6. (c) Zn being more reactive than Ag and Au, displaces them.
4Ag + 8NaCN + 2H
2
O + O
2
 4Na[Ag(CN)
2
] + 4NaOH
Sodium dicyanoargentate (I)
Soluble
Soluble cyanide compound can be treated with Zn to give metal by
displacement.
2Na[Ag(CN)
2
] + Zn   Na
2
[Zn(CN)
4
] + 2Ag?
7. (d) Decomposition of carbonates and hydrated oxides.
8. (c)
9. (b) Pig iron or cast iron contains 3 – 5% carbon and varying amounts
of Mn, Si, P and S which makes the iron hard and brittle.
10. (b) Cuprite is Cu
2
O and Argentite is .
11. (b) Cyanide process is for gold (I-D); floatation process - pine oil (II-
B); Electrolytic reduction - Al (III-C); Zone refining -Ge (IV-A).
12. (b) For a spontaneous reaction , ? Gº must be negative and it can be
possible only in this case when x < y.
13. (c) Fused alumina (Al
2
O
3
) is a bad conductor of electricity. Therefore,
cryolite (Na
3
AlF
6
) and fluorspar (CaF
2
) are added to purified
alumina which not only make alumina a good conductor of
electricity but also reduce the melting point of the mixture to
around 1140 K.
14. (d) The sulphide ore is roasted to oxide before reduction because the 
 of most of the sulphides are greater than those of CS
2
 and
H
2
S, therefore neither C nor H can reduce metal sulphide to metal.
Further, the standard free energies of formation of oxide are much
less than those of SO
2
. Hence oxidation of metal sulphides to metal
oxide is thermodynamically favourable.
15. (a) Cuprous oxide formed during roasting of cuprous sulphide is
mixed with few amount of cuprous sulphide and heated in a
reverberatory furnace to get metallic copper.
16. (a) Zone refining is based on the difference in solubility of impurities
in molten and solid state of the metal. This method is used for
obtaining metals of very high purity.
17. (b) The reactions involved in cyanide extraction process are :
 +  4NaCN ?  2Na [Ag(CN)
2
] + Na
2
S
4Na
2
S + + 2H
2
O ? 2Na
2
SO
4
 + 4NaOH + 2S
2Na[Ag(CN)
2
] + ? Na
2
 [Zn(CN)
4
] + 2 Ag
18. (b) Al
2
O
3
 cannot be reduced by carbon.
19. (b) The given reaction is the method named as Van Arkel  for the
purification of titanium.
20. (c) Ca and K are strong reducing agents, hence their oxides  cannot be
reduced with carbon.
21 (b) Zr and Ti are purified by van Arkel method.
Page 3


1. (a) The conversion of metal sulphide to metal oxide involves the
process of roasting (i.e., x is roasting).
The metal oxides can then be converted to impure metal by reduction.
Of the given choices in (a) and (b) the reduction process is that of
smelting. (i.e., ‘y’ is smelting)
The conversion of impure metal to pure metal involves a process of
purification. Thus it is electrolysis.
2. (b)
3. (c)
4. (b)
5. (a) Dolomite on calcination gives CaO, MgO which provides basic
lining in furnace.
6. (c) Zn being more reactive than Ag and Au, displaces them.
4Ag + 8NaCN + 2H
2
O + O
2
 4Na[Ag(CN)
2
] + 4NaOH
Sodium dicyanoargentate (I)
Soluble
Soluble cyanide compound can be treated with Zn to give metal by
displacement.
2Na[Ag(CN)
2
] + Zn   Na
2
[Zn(CN)
4
] + 2Ag?
7. (d) Decomposition of carbonates and hydrated oxides.
8. (c)
9. (b) Pig iron or cast iron contains 3 – 5% carbon and varying amounts
of Mn, Si, P and S which makes the iron hard and brittle.
10. (b) Cuprite is Cu
2
O and Argentite is .
11. (b) Cyanide process is for gold (I-D); floatation process - pine oil (II-
B); Electrolytic reduction - Al (III-C); Zone refining -Ge (IV-A).
12. (b) For a spontaneous reaction , ? Gº must be negative and it can be
possible only in this case when x < y.
13. (c) Fused alumina (Al
2
O
3
) is a bad conductor of electricity. Therefore,
cryolite (Na
3
AlF
6
) and fluorspar (CaF
2
) are added to purified
alumina which not only make alumina a good conductor of
electricity but also reduce the melting point of the mixture to
around 1140 K.
14. (d) The sulphide ore is roasted to oxide before reduction because the 
 of most of the sulphides are greater than those of CS
2
 and
H
2
S, therefore neither C nor H can reduce metal sulphide to metal.
Further, the standard free energies of formation of oxide are much
less than those of SO
2
. Hence oxidation of metal sulphides to metal
oxide is thermodynamically favourable.
15. (a) Cuprous oxide formed during roasting of cuprous sulphide is
mixed with few amount of cuprous sulphide and heated in a
reverberatory furnace to get metallic copper.
16. (a) Zone refining is based on the difference in solubility of impurities
in molten and solid state of the metal. This method is used for
obtaining metals of very high purity.
17. (b) The reactions involved in cyanide extraction process are :
 +  4NaCN ?  2Na [Ag(CN)
2
] + Na
2
S
4Na
2
S + + 2H
2
O ? 2Na
2
SO
4
 + 4NaOH + 2S
2Na[Ag(CN)
2
] + ? Na
2
 [Zn(CN)
4
] + 2 Ag
18. (b) Al
2
O
3
 cannot be reduced by carbon.
19. (b) The given reaction is the method named as Van Arkel  for the
purification of titanium.
20. (c) Ca and K are strong reducing agents, hence their oxides  cannot be
reduced with carbon.
21 (b) Zr and Ti are purified by van Arkel method.
22. (d) Zincite is ZnO.
23. (a) FeO is capable forming slag with SiO
2
24. (d)
25. (b) The two equation are:
… (1)
… (2)
Subtracting equation (ii) from equation (i) we have,