Extraction of Aluminium

Q.

The chemical formula of sulfur is?

Q. The correct formula of dolomite is:

1. $CaC{O}_3.MgC{O}_3$
2. $CaC{O}_3.ZnC{O}_3$
3. $MgC{O}_3.ZnC{O}_3$
4. $FeC{O}_3.CaC{O}_3$

Q.

Why a dry cell becomes dead after a long time even it has not been used?

1. because electrolyte undergoes decomposition

2. because it discharges slowly

3. because zinc reacts with the ammonium chloride

4. because it requires an optimum temperature to work

Q.

Formula of hydroxyapatite is?

1. $\left(\mathrm{CaPO}4\right)6.\mathrm{CaF}2$

2. $3\left[\mathrm{Ca}3\right(\mathrm{PO}4\left)2\right].\mathrm{Ca}\left(\mathrm{OH}\right)2$

3. $3\left[\mathrm{Ca}3\right(\mathrm{PO}4\left)2\right].\mathrm{CaF}2$

4. $\mathrm{Ca}3\left(\mathrm{PO}4\right)2.\mathrm{Ca}\left(\mathrm{OH}\right)2$

Q. Aluminum is extracted from alumina ($A{l}_2{O}_3$) by electrolytes of a molten mixture of

1. $A{l}_2{O}_3+HF+NaAl{F}_4$
2. $A{l}_2{O}_3+Ca{F}_2+NaAl{F}_4$
3. $A{l}_2{O}_3+N{a}_{3}Al{F}_6+Ca{F}_2$
4. $A{l}_2{O}_3+KF+N{a}_{3}Al{F}_6$

Q. Sulphide ores of metal are usually concentrated by froth floatation process. Which one of the following sulphide ores offer an exception and is concentrated by chemical leaching?

1. Galena
2. Copper pyrite
3. Sphalerite
4. Argentite

Q.

Match list-I with list-II

Column 1	Column 2
Siderite	$\mathrm{Cu}$
Calamine	$\mathrm{Fe}$
Malachite	$\mathrm{Al}$
Cryolite	$\mathrm{Zn}$

Q. Magnesite is an ore of magnesium whose chemical composition is :

1. $MgS{O}_4.H_{2}O$
2. $MgC{O}_3$
3. $A{g}_{2}S$
4. None of the above

Q.

What is the chemical formula of Aluminium sulfate?

Q.

What is the temperature needed to bend aluminum?

Q. In ternary and Quaternary solution what is the third and fourth component called respectively?

Q.

Why is copper easily shaped?

Q. When borax is heated with CoO on a platinum loop, blue coloured bead formed is

1. $Co\left[B_4{O}_5\right(OH{)}_4]$
2. $Co(B{O}_2{)}_2$
3. $B_2{O}_3$
4. $Co{B}_4{O}_7$

Q.

Aluminium powder is used in thermite welding because:

1. it is a strong reducing agent

2. it is a strong oxidising agent

3. it is a corrosion resistant

4. it is a good conductor of heat

Q.

The correct set of carbonate ores is (i) dolomite (ii) anglesite (iii) cuprite (iv) malachite (v) argentite (vi) siderite

Q. An uranium ore sample contains 1g U^238 and 0.2 g Pb^206. Assume that all Pb ^206 is obtained from U^238. The t1/2 of U^238 is 4.5 ×10^9 years. The age of Uranium ore sample is Option (1) 3× 10^9 (2) 1.5× 10^9 (3) 4×10^9 (4)3× 10^8

Q. 7.What is the differences between smelting and bessemerisation process of copper

Q. Q. Arrange in the thermal stability order of carbonates
Na2CO3, K2CO3, BeCO3, BaCO3

Q. Which of the following does not evolve oxygen at anode when electroysis is carried?

Given:
$E_{Cu/C{u}^{2+}}^0=-0.34V$
$E_{H_{2}O/O_2}^0=-1.23V$

1. $dil.H_{2}S{O}_4$ with Pt electrode
2. Fused $NaOH$ with $Pt$ electrode
3. Acidic water with $Pt$ electrode
4. $dil.H_{2}S{O}_4$ with $Cu$ electrode

Q. which of the following statements is not correct? 1.In froth floatation process, pine oil decreases thesurface tension of the solution (2) Van Arkel method is used for refining zirconium (3) Dolomite ore can be considered as ore of bothCa and Mg (4) Aqueous Al2 (SO4)3 is used for electrorefiningof Al

Q.

How can you separate alumina from silica in a bauxite are associated with silica? Give equatiions, if any.

Q. The Mond process is used for the:

1. Extraction of $Mo$
2. Purification of $Ni$
3. Purification of $Zr$ and $Ti$
4. Extraction of $Zn$

Q.

The role of fluorspar $\left(Ca{F}_2\right)$ which is added in small quantities in the electrolytic reduction of alumina dissolved in fused cryolite $\left(N{a}_{3}Al{F}_6\right)$ is:

1. to decrease the rate of oxidation of carbon at the anode

2. to increase the temperature of the melt

3. as a catalyst

4. to make the fused mixture very conducting

Q.

Can aluminium be extracted from bauxite through hydrometallurgy?

Q.

What is the role of cryllite in the metallurgy of aluminimum?

Q. Discuss the trend of the following:-
(1) Thermal stability of carbonates of group 2 elements
(2) The solubility and the nature of oxides of group 2 elements.

Q. In the context of the Hall-Heroult process for the extraction of Al, which of the following statements is false?

1. $CO$ and $C{O}_2$ are produced in this process

2. $A{l}_2{O}_3$ is mixed with $Ca{F}_2$, which lowers the melting point of the mixture and brings conductivity

3. $A{l}^{3+}$ is reduced at the cathode to form $Al$

4. $N{a}_{3}Al{F}_6$ serves as the electrolyte

Q.

Ball mill or stamp mill are used in crushing and grinding of ores

1. True

2. False

Q.

Bauxite is an ore of zinc.

1. True
2. False

Q. Copper matte is: