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14
MCQ (Multiple Correct Answer)

At the temperature corresponding to which of the points in Fig. FeO will be reduced to Fe by coupling the reaction $2 \mathrm{FeO} \longrightarrow \mathrm{WFe}+\mathrm{O}_2$ with all of the following reactions?

$$\text { 1. } \mathrm{C}+\mathrm{O} \longrightarrow \mathrm{CO}_2$$

$$\begin{aligned} & \text { 2. } 2 \mathrm{C}+\mathrm{O}_2 \longrightarrow 2 \mathrm{CO} \\ & \text { 3. } 2 \mathrm{CO}+\mathrm{O}_2 \longrightarrow 2 \mathrm{CO}_2 \end{aligned}$$

A
Point $A$
B
Point $B$
C
Point $D$
D
Point $E$
15
MCQ (Multiple Correct Answer)

Which of the following options are correct?

A
Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast.
B
In extraction of silver, silver is extracted as cationic complex.
C
Nickel is purified by zone refining.
D
Zr and Ti are purified by van Arkel method.
16
MCQ (Multiple Correct Answer)

In the extraction of aluminium by Hall-Heroult process, purified $\mathrm{Al}_2 \mathrm{O}_3$ is mixed with $\mathrm{CaF}_2$ to

A
lower the melting point of $\mathrm{Al}_2 \mathrm{O}_3$
B
increase the conductivity of molten mixture.
C
reduce $\mathrm{Al}^{3+}$ into $\mathrm{Al}(\mathrm{s})$
D
acts as catalyst
17
MCQ (Multiple Correct Answer)

Which of the following statements is correct about the role of substances added in the froth floatation process?

A
Collectors enhance the non-wettability of the mineral particles.
B
Collectors enhance the wettability of gangue particles.
C
By using depressants in the process two sulphide ores can be separated.
D
Froth stabilisers decrease wettability of gangue.
18
MCQ (Multiple Correct Answer)

In the froth floatation process, zinc sulphide and lead sulphide can be separated by ............ .

A
using collectors
B
adjusting the proportion of oil to water
C
using depressant
D
using froth stabilisers
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