Leaching

Q.

Leaching is a process of

1. Reduction

2. Concentration

3. Oxidation

4. Refining

Q.

what happens when crystals of potassium permanganate is heated to 513k?

Q. Extraction gold and silver involves leaching with $C{N}^{-}$ ion. Silver is later recovered by:

1. Liquation
2. Distillation
3. Zone refining
4. Displacement with $Zn$

Q. Given below are two statements :

Statement I : Sphalerite is a sulphide ore of zinc and copper glance is a sulphide ore of copper .

Statement II : It is possible to separate two sulphide ores by adjusting proportion of oil to water or by using depressants in a froth flotation method .

Choose the most appropriate answer from the options given below :

1. Statement I is true but Statement II is false
2. Statement I is false but Statement II is true
3. Both Statement I and Statement II are false
4. Both Statement I and Statement II are true

Q.

The principal involved in leaching

A.)difference in volatility

B.)difference in density

C.)difference in solubility

D.)soluble complex formation

Q. Process of roasting

Q. Roasting is done for sulphide ores then how roasting of haematite ore can be performed in the metallurgy of iron??

Q.

Which is an ore of potassium

1. Dolomite

2. Carnellite

3. Cryolite

4. Bauxite

Q.

When $\mathrm{Zn}$ granules are added to dilute ${\mathrm{H}}_2{\mathrm{SO}}_4$, which of the following reactions takes place?

1. $\mathrm{Zn}$ gets oxidized

2. $\mathrm{Zn}$ gets reduced

3. $\mathrm{Zn}$ gets displaced

4. $\mathrm{Zn}$ gets vaporized

Q.

What is the use of Baeyers process in leaching?

Q. Write the chemical reactions involved in the process of extraction of Gold. Explain the role of dilute NaCN and Zn in this process.

Q.

Why pyrometallurgy is used in the process of metallurgy is it helpful for us

Q. The methods chiefly used for the reduction of ores of lead and tin are respectively.

1. Self reduction and carbon reduction
2. Self reduction and electrolytic reduction
3. Carbon reduction and self reduction
4. Cynide process and carbon reduction

Q.

Select the false statements, during concentration of ore.

1. Roasting involves heating the ores strongly in presence of air with or without certain substances below their melting points.

2. Calcination involves heating the ores strongly in the absence of air, above its melting point.

3. On Calcination or Roasting the metallic ore is converted into its corresponding oxide.

4. None of the above

Q.

How is leaching carried out in case of low grade copper ores?

Q.

What is the role of NaOH in the metallurgy of Aluminium?

Q. What is resin? Whats its use in numerical

Q.

leaching of gold or silver involves a disproportionation reaction justify

I have exam today. Please explain.....

Q.

What is the process of leaching?

Q.

What is the function cryolite in the extraction of $\mathrm{Al}$, other than dissolving bauxite.

Q. Extraction of aluminium in detail

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

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

Q.

What is meant by leaching?

Q.

What is the role of depressants in the Froth Floatation Process?

Q. Chemical leaching is useful in the concentration of:

1. bauxite
2. copper pyrities
3. cassiterite
4. galena

Q. Why is leaching used as the method of concentration for bauxite ore?

Q. 7.What is the process of leaching in case of low grade copper ores?

Q. Chemical leaching is useful in the concentration of:

1. galena
2. bauxite
3. cassiterite
4. copper pyrities

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

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

Q. leching of ore is done by? plese give explanation as to why serpecks method is not chosen. a)halls process b)serpecks process c)cyanide process d)hall-heroults process