Ores and Metallurgy MCQ Questions & Answers in Inorganic Chemistry | Chemistry
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41.
Why is partial roasting of sulphide ore done in metallurgy of copper?
A
Auto-reduction of $$C{u_2}O$$ formed is carried out by remaining $$C{u_2}S$$ in the reaction.
B
$$Cu$$ is separated out by partial reduction due to sedimentation.
C
Due to difference in gravity $$C{u_2}O$$ and $$C{u_2}S$$ are separated.
D
Complete roasting cannot be done in one step hence partial roasting is done.
Answer :
Auto-reduction of $$C{u_2}O$$ formed is carried out by remaining $$C{u_2}S$$ in the reaction.
Partial roasting of sulphide ore forms some oxide. This oxide then reduces the remaining sulphide ore into metal.
$$\eqalign{
& 2C{u_2}S + 3{O_2} \to 2C{u_2}O + 2S{O_2} \cr
& 2C{u_2}O + C{u_2}S \to 6Cu + S{O_2} \cr} $$
This process is called auto reduction.
42.
Which one of the following is not a sulphide ore?
44.
Extraction of gold and silver involves leaching the metal with $$C{N^ - }$$ ion. The metal is recovered by _________.
A
displacement of metal by some other metal from the complex ion
B
roasting of metal complex
C
calcination followed by roasting
D
thermal decomposition of metal complex
Answer :
displacement of metal by some other metal from the complex ion
No explanation is given for this question. Let's discuss the answer together.
45.
Correct match is :
A
Bayer's method $$ - \,N{a_2}C{O_3}$$
B
Matte $$ - \,98\% \,C{u_2}S + 2\% FeS$$
C
van Arkel method $$ - \,AgI$$
D
Thomas slag - Raw material for cement industry
Answer :
Matte $$ - \,98\% \,C{u_2}S + 2\% FeS$$
Roasted mass obtained from roasting step is called matte. $$\left( {98\% \,C{u_2}S + 2\% FeS} \right)$$
46.
Match the column I with column II to match the method of extraction and mark the appropriate choice.
Column I
Column II
a.
$$Cu$$
1.
Direct reduction of sulphide by heating
b.
$$Sn$$
2.
Electrolysis of fused Chloride and fluoride
c.
$$Hg$$
3.
Partial oxidation of sulphide ore
d.
$$Ca$$
4.
Reduction of oxide with carbon
A
a - 3, b -1 , c - 2, d - 4
B
a - 3, b - 4, c - 1, d - 2
C
a - 1, b- 3, c - 2, d - 4
D
a - 4, b - 1, c - 2, d - 3
Answer :
a - 3, b - 4, c - 1, d - 2
No explanation is given for this question. Let's discuss the answer together.
47.
Froth floatation process of concentration is based on the
A
preferential wetting properties with the frothing agent and water
B
difference in the specific gravities of gangue and ore particles
C
difference in solubility of gangue and ore particles in frothing agent and water
D
difference in reactivity of gangue and ore particles with water and frothing agent.
Answer :
preferential wetting properties with the frothing agent and water
No explanation is given for this question. Let's discuss the answer together.
48.
In the alumino-thermite process, aluminium acts as
A
an oxidizing agent
B
a flux
C
a reducing agent
D
a solder
Answer :
a reducing agent
Al reduces $$F{e_2}{O_3}\,\,{\text{or}}\,\,C{r_2}{O_3}$$ to respective metals and acts as a reducing agent.
$$F{e_2}{O_3} + 2Al \to A{l_2}{O_3} + 2Fe$$
49.
Which of the following elements is present as the impurity to the maximum extent in the pig iron?
A
Carbon
B
Silicon
C
Phosphorus
D
Manganese
Answer :
Carbon
Pig iron contains about 4% carbon ( major impurity ) and other impurities $$(S, P, Si, Mn)$$ in trace amounts.
50.
Refractory materials are generally used in furnaces because
A
they possess great structural strength
B
they can withstand high temperature
C
they are chemically inert
D
they do not require replacement
Answer :
they can withstand high temperature
Refractories are the substances which can withstand very high temperature without melting or becoming soft.