101.
Which one of the following ores is not concentrated by froth floatation process? A
Copper pyrites
B
Pyrargyrite
C
Pyrolusite
D
Zinc blende
Answer :
Pyrolusite
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Pyrolusite is $$Mn{O_2}.$$ Hence not concentrated by froth floatation process.
102.
In which of the following the name of the ore is not matched with its formula? A
Cassiterite - $$ Sn{O_2}$$
B
Limonite - $$ F{e_2}{O_3} \cdot 3{H_2}O$$
C
Siderite - $$ FeC{O_3}$$
D
Anglesite - $$ PbC{O_3}$$
Answer :
Anglesite - $$ PbC{O_3}$$
103.
Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true? A
Carbon and hydrogen are suitable reducing agents for metal sulphides
B
The $${\vartriangle _f}{G^ \circ }$$ of the sulphide is greater than those for $$C{S_2}$$ and $${H_2}S$$
C
The $${\vartriangle _f}{G^ \circ }$$ is negative for roasting of sulphide ore to oxide
D
Roasting of the sulphide to the oxide is thermodynamically feasible
Answer :
Carbon and hydrogen are suitable reducing agents for metal sulphides
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Carbon and hydrogen are not suitable reducing agents for metal sulphides.
104.
During smelting an additional substance is added which combines with impurities to form a fusible product. It is known as A
slag
B
mud
C
gangue
D
flux
Answer :
flux
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Flux is added which combines with impurities to form slag.
105.
Heating pyrites to remove sulphur is called A
smelting
B
calcination
C
liquation
D
roasting
Answer :
roasting
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106.
The materials which can withstand very high temperature without melting or becoming soft are called _________. These are used in making _________ of furnaces. A
refractory materials, inner lining
B
flux, base
C
brick materials, outer structure
D
mica, outer lining
Answer :
refractory materials, inner lining
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107.
Extraction of zinc from zinc blende is achieved by A
electrolytic reduction
B
roasting followed by reduction with carbon
C
roasting followed by reduction with another metal
D
roasting followed by self-reduction
Answer :
roasting followed by reduction with carbon
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NOTE : Extraction of $$Zn$$ from $$ZnS$$ (Zinc blende) is achieved by roasting followed by reduction with carbon.
108.
Which of the following reactions takes place at higher temperature range $$\left( {900\,K - 1500\,K} \right)$$ in blast furnace? A
$$3F{e_2}{O_3} + CO \to 2F{e_3}{O_4} + C{O_2}$$
B
$$FeO + CO \to Fe + C{O_2}$$
C
$$F{e_3}{O_4} + 4CO \to 3Fe + 4C{O_2}$$
D
$$F{e_2}{O_3} + CO \to 2FeO + C{O_2}$$
Answer :
$$FeO + CO \to Fe + C{O_2}$$
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At $$900 - 1500\,K$$ the reactions taking place in blast furnace are : $$C + C{O_2} \to 2CO,$$ $$FeO + CO \to Fe + C{O_2}$$
109.
Wrought iron is manufactured from cast iron by heating it with A
$$C$$
B
$$CaC{O_3}$$
C
$$F{e_2}{O_3}$$
D
$$Si{O_2}$$
Answer :
$$F{e_2}{O_3}$$
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When cast iron is heated with $$F{e_2}{O_3},C$$ and $$Mn$$ are removed the resulting metal is wrought iron.
110.
_______ being highly reactive is used in the extraction of chromium and manganese. A
$$Al$$
B
$$Zn$$
C
$$Cu$$
D
$$Mg$$
Answer :
$$Al$$
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