Baeyer's Process

Q. The basic structural unit of feldspar, zeolites, mica and asbestos is:

1. ${\left(Si{O}_3\right)}^{2-}$

2. $Si{O}_3$

3. ${\left(Si{O}_4\right)}^{4-}$

4. 

Q. In the extraction of aluminium by Hall-Heroult process, purified $A{l}_2{O}_3$ is mixed with $Ca{F}_2$ to:

1. Lower the melting point of $A{l}_2{O}_3$ mixture
2. Increase the conductivity of molten mixture
3. Reduce $A{l}^{3+}$ into $Al\left(s\right)$
4. Acts as catalyst

Q. Match List I with List II and select the correct answer using the codes given below the list : -

$\begin{array}{cc}\text{List - I}& \text{List - II}\\ \text{(Metals)}& (\text{Extraction Process)}\\ \text{(a)}Au& \left(1\right)\text{Self reduction}\\ \text{(b)}Al& \left(2\right)\text{Liquation}\\ \text{(c)}Pb& \left(3\right)\text{Electrolysis}\\ \text{(d)}Sn& \left(4\right)\text{Bayer process}\end{array}$

1. a - 3, b - 1, c - 2, d - 4
2. a - 1, b - 2, c - 4, d - 3
3. a - 3, b - 4, c - 1, d - 2
4. a - 3, b - 2, c - 4, d - 1

Q. Which of the following statements is correct regarding the slag obtained during the extraction of a metal like copper or iron?

1. The slag is lighter and has lower melting point than the metal
2. The slag is heavier and has lower melting point than the metal
3. The slag is lighter and has higher melting point than the metal
4. The slag is heavier and has higher melting point than the metal

Q. Which of the following reactions does not take place during leaching for concentration of bauxite?

1. $A{l}_2{O}_3\left(s\right)+2NaH\left(aq\right)+3H_{2}O\left(l\right)\to 2Na\left[Al\right(OH{)}_4\left]\right(aq)$
2. $2Na\left[Al\right(OH{)}_4\left]\right(aq)+C{O}_2(g)\to A{l}_2{O}_3.x{H}_{2}O(s)+2NaHC{O}_3(aq)$
3. $A{l}_2{O}_3\left(s\right)+2NaOH\left(aq\right)+3H_{2}O\left(l\right)\to 2Na\left[Al\right(OH{)}_4\left]\right(aq)$
4. $A{l}_2{O}_3.x{H}_{2}O\left(s\right)\stackrel{1470K}{\to }A{l}_2{O}_3\left(s\right)+xH2O\left(g\right)$

Q. What is the term given to the extraction of aluminium from bauxite by using electrochemical process?

1. Baeyer’s process
2. Hall-Heroult process
3. Mc-Arthur process
4. Blasts process

Q. Which of the desiccants can be used to remove moisture from $S{O}_2$ ?

1. $conc.H_{2}S{O}_4$
2. $KOH$
3. $P_2{O}_5$
4. $K_{2}C{O}_3$

Q. Which among the following statement(s) is(are) true for the extraction of aluminium from bauxite?

1. Hydrated $A{l}_2{O}_3$ precipitates, when $C{O}_2$ is bubbled through a solution of sodium aluminate.
2. Addition of $N{a}_{3}Al{F}_6$ lowers the melting point of alumina.
3. $C{O}_2$ is evolved at the anode during electrolysis
4. The cathode is a steel vessel with a lining of carbon.

Q. Which among the following statement(s) is(are) true for the extraction of aluminium from bauxite?

1. $C{O}_2$ is evolved at the anode during electrolysis
2. Addition of $N{a}_{3}Al{F}_6$ lowers the melting point of alumina.
3. Hydrated $A{l}_2{O}_3$ precipitates, when $C{O}_2$ is bubbled through a solution of sodium aluminate.
4. The cathode is a steel vessel with a lining of carbon.

Q. Observe the following statements regarding purification of bauxite:
I. During Hall's process, silica is removed as Si (vapour).
II. Bauxite ore contaminated with $F{e}_2{O}_3$ is purified in Baeyer's process.
III. During Serpeck's process, $AlN$ is formed.

1. Only II and III are correct
2. I , II and III are correct
3. Only I and III are correct
4. Only I and II are correct

Q.

In Bayer’s leaching process, the siliceous impurities $\left(Si{O}_2\right)$ are filtered out immediately after leaching with NaOH – True or False?

1. True

2. False

Q.

In Red Bauxite, the major impurity is $Ti{O}_2$ – True or False?

1. True

2. False

Q. Match List I with List II and select the correct answer using the codes given below the list : -

$\begin{array}{cc}\text{List - I}& \text{List - II}\\ \text{(Metals)}& (\text{Extraction Process)}\\ \text{(a)}Au& \left(1\right)\text{Self reduction}\\ \text{(b)}Al& \left(2\right)\text{Liquation}\\ \text{(c)}Pb& \left(3\right)\text{Electrolysis}\\ \text{(d)}Sn& \left(4\right)\text{Bayer process}\end{array}$

Q. The diagram shows the sketch of an electrolytic cell used in the extraction of aluminium. What is the substance of which the electrodes A and B are made?

1. Carbon and graphite
2. Zinc and copper
3. None of the above
4. Copper and iron

Q. If Bauxite consists of $Si{O}_2$ as impurity, the process employed is:

1. Hall's process
2. Baeyer's process
3. Hoope's process
4. Serpeck's process