Cyanide or Macarthur Forrest Process

Q.

Write a balanced chemical equation for sodium to react with oxygen.

Q.

What are Zinc granules? Explain with examples.

Q.

Which of the following is a redox reaction

1. 

2. 

3. 

4. 

Q. Leaching of gold with dilute aqueous solution of $NaCN$ in presence of oxygen gives complex [A], which on reaction with zinc forms the elemental gold and another complex [B]. [A] and [B], respectively are :

Q. Cyanide process is used for the extraction of:

1. Both Au and Ag
2. Au
3. Ag
4. Al

Q.

How is Silver extracted?

Q.

Removal of impurities from ore is known as -

1. Crushing and grinding

2. Concentration of ore

3. Minerals

4. Gangue

Q. hybridisation of co(nh3)4 2+ is

Q.

Name a hydroxide which is soluble in excess of ammonium hydroxide.

Q. In isolation of which one of the following metals from their ores, the use of cyanide salt is not commonly involved?

Q. Why hybridization of [Cr(H2O)6]³ is sp³d² and not d²sp³??

Q. ZnO is white when cold and yellow when hot because it____.

1. sublimes
2. melts
3. all of the above
4. forms a non-stoichiometric compound at high temperatures

Q.

State one observation for the following:

Excess ammonium hydroxide solution is added to lead nitrate solution.

Q. Mac Arthur process is used for:

1. $Ag$
2. $O_2$
3. $Fe$
4. $Cl$

Q. Given below are two statements .

Statement I : The choice of reducing agents for metals extraction can be made by using Ellingham diagram , a plot of $\Delta G$ vs temperature.

Statement II : The value of $\Delta S$ increases from left to right in Ellingham diagram .

In the light of the above statements , 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. Ionic hydrides react with water to give:

1. Acidic solutions
2. Basic solutions
3. Hydride ion
4. Protons

Q.

The electrolyte used for electroplating an article with silver is:

1. Silver nitrate solution

2. Silver cyanide solution

3. Sodium argentocyanide solution

4. nickel sulphate solution

Q. $A_1$ and $A_2$ are two ores of metal $M.$

1. $C{u}_{2}S,Cu(OH{)}_2.CuC{O}_3$
2. $CaC{O}_3,C{u}_{2}S$
3. $C{u}_{2}S,CaC{O}_3$
4. $Cu(OH{)}_2.CuC{O}_3,C{u}_{2}S$

Q. Extraction of gold and silver involves leaching the metal with $C{N}^{-}$ ion. The metal is recovered by:

1. roasting of metal complex
2. displacement of metal by some other metal from the complex ion
3. calcination followed by roasting
4. thermal decomposition of metal complex

Q. Which of the following Equation represents the value of $\Delta H_f^0$ of $AgI$?

1. Ag (g) + 1/2 I₂(g) →Ag I (s)

2. 2Ag (s) + I₂(g) →2 Ag I(s)

3. Ag (s) + 1/2 I₂(g) →Ag I (s)

4. Ag⁺(aq) + I^- (aq)→AgI(s)

Q.

Reaction of magnesium(Mg) and boiling water is a fast process.

1. True
2. False

Q. In the process of extraction of gold,
$\text{Roasted gold ore}+C{N}^{-}+H_{2}O\stackrel{O_2}{⟶}\left[X\right]+O{H}^{-}$
$\left[X\right]+Zn\to \left[Y\right]+Au$
Identify the complexes [X] and [Y]

1. $X=\left[Au\right(CN{)}_4{]}^{-},Y=\left[Zn\right(CN{)}_4{]}^{2-}$
2. $X=\left[Au\right(CN{)}_4{]}^{3-},Y=\left[Zn\right(CN{)}_4{]}^{2-}$
3. $X=\left[Au\right(CN{)}_2{]}^{-},Y=\left[Zn\right(CN{)}_4{]}^{2-}$
4. $X=\left[Au\right(CN{)}_2{]}^{-},Y=\left[Zn\right(CN{)}_6{]}^{4-}$

Q. How is gold extracted from its ore?

Q. Among these ores the highest phosphorus content is in :

1. chlorapatite.
2. phosphorite.
3. fluorspar.
4. equal.

Q.

Answer in one word: Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.

Q.

Refining of silver is done by

1. Polling

2. Van arkel method

3. liquation

4. cupellation

Q. At 25 o C, the dissociation constant of a base, BOH is 1.0×10 −12 . The concentration of hydroxyl ions in 0.01M aqueous solution of the base would be:

Q. Name the important ore of silver. Write all the steps and reactions involved in the Cyanide process for the extraction of silver from its ore.

Q. Statement 1: Leaching is employed in the extraction of aluminium, silver and gold.

1. Statement 1 and statement 2 are true and statement 2 is a correct explanation of statement 1.
2. Statement 1 and statement 2 are true but statement 2 is not a correct explanation of statement 1.
3. Statement 1 is true and statement 2 is false.
4. Statement 1 is false and statement 2 is true.

Q. (a) Which solution is used for the leaching of silver metal in the presence of air in the metallurgy of silver?
(b) Out of 'C' and 'CO', which is a better reducing agent at the lower temperature range in the blast furnace to extract iron from the oxide ore?