The basic principle of froth floatation is-

1.	Impurities and metal ore have different wetting properties.
2.	Impurities and metal ore have different solubility.
3.	Impurities and metal ore have different diversity.
4.	Impurities and metal ore have different compressing power.

Out of the following which metal can be purified by Van Arkel method?

1.  Au

2.  Zr

3.  Ag

4.  Cu

During electrolysis of fused NaCl in order to obtain Na, ${\mathrm{H}}_2$ is liberated at the cathode of Pt while with the cathode of Hg, it forms sodium amalgam. This is because

(I)  Pt is inert

(2)  Hg is a liquid

(3)  More voltage is required to produce ${\mathrm{H}}_2$ at Hg than at Pt

(4)  ${\mathrm{H}}^{\oplus }$ ions are formed rapidly when Hg is used as a cathode

Which of the following is an incorrect match?

1. Kaolinite - Al₂(OH)₄Si₂O₅

2. Cuprite - Cu₂O

3. Siderite - FeCO₃

4. Calamine - ZnSO₄

Among the following a non-oxide ore is:

1. Malachite

2. Cuprite

3. Zincite

4. Bauxite

Mg in the Kroll process acts as

(1)  Reducing agent

(2)  Oxidizing agent

(3)  Oxidizing agent at low temperature

(4)  Reducing agent at low temperature

Out of the following which is a hydride?

(1)  Hydrolith

(2)  Oxidane

(3)  Azane

(4)  All of these

The process of converting hydrated alumina into anhydrous alumina is called

(1)  Roasting

(2)  Smelting

(3)  Dressing

(4)  Calcination

2MS + 3O₂ → 2MO + 2SO₂
2MO + MS → 3M + SO₂

The metal M in above-mentioned reaction is:

1. Mg

2. Pb

3. Sn

4. Fe

Consider the following reaction.
\(\small{Bauxite\ ore\ +\ NaOH\ (conc.) \xrightarrow[\Delta]{Digester} \underset{Soluble}{(A)}}\)
\((A) \xrightarrow{Fresh\ Al(OH)_3}\ \underset{White}{(B)}\ +\ (C)\)
\({(B)} \xrightarrow[]{\Delta}\ (D)\ +\ H_2O\)
What is the molecular formula of compound D?

1. ${\mathrm{NaAlO}}_2$

2. $\mathrm{Al}{\left(\mathrm{OH}\right)}_3$

3. ${\mathrm{Al}}_2{\mathrm{O}}_3$

4. ${\mathrm{Na}}_2\mathrm{O}$