Roasting

Q.

Extraction of copper is done using copper pyrites. After roasting, the ore is mixed with silica and coke and then smelted in a blast furnace. The matte obtained from the blast furnace is charged into a silica-lined converter. Some silica is also added, and a hot air blast is blown into the mixture to obtain blister copper, which is purified by electrorefining. The chemical composition of the slag formed during smelting is:

1. ${\mathrm{CuSiO}}_3$

2. ${\mathrm{CaSiO}}_3$

3. ${\mathrm{FeSiO}}_3$

4. None of these

Q.

In the double displacement reaction between aqueous Potassium iodide and aqueous Lead nitrate, a yellow precipitate of Lead iodide is formed. While performing the activity if lead Nitrate is not available, which of the following can be used in place of Lead nitrate?

1. Lead sulphate (insoluble)

2. Lead acetate

3. Ammonium nitrate

4. Potassium sulphate

Q.

Giving example, differentiate between roasting and calcination.

Q.

What happens when (a) ${\mathrm{ZnCO}}_3$is heated in the absence of oxygen? (b) a mixture of ${\mathrm{Cu}}_2\mathrm{O}$ and ${\mathrm{Cu}}_2\mathrm{S}$is heated?

Q. Read the following statements carefully.

(I) Sulphide ores are converted into oxides by heating strongly in the absence of air or oxygen.

(II) Impurities such as soil, sand etc, present in ores are called gangue.

Now, choose the correct option.

1. 
   Only statement (I) is correct
2. 
   Only statement (II) is correct
3. 
   Both the statements are correct
4. 
   Both the statements are incorrect

Q. What are the features of Ellingham diagram? What is its significance?

Q. Which of the following reactions are examples of roasting?

1. ${\text{CaCO}}_3\text{(s)}$ $\to$ $\text{CaO (s)}+{\text{CO}}_2\text{(g)}$
2. $4{\text{FeS}}_2\text{(s)}$ + ${\text{11O}}_2\text{(g)}$ $\to$ $2{\text{Fe}}_2{\text{O}}_3\text{(s)}$ + $8{\text{SO}}_2\text{(g)}$
3. $2{\text{Al(OH)}}_3\text{(s)}$ $\to$ ${\text{Al}}_2{\text{O}}_3\text{(s)}$ + ${\text{3H}}_2\text{O (l)}$
4. $2\text{CuS(s)}$+ $2{\text{O}}_2\text{(g)}$ $\to$ $2\text{Cu(s)}$ + ${\text{2SO}}_2\text{(g)}$

Q.

Give the steps involved in the extraction of metals of low and medium reactivity from their respective sulphide ores

Q. Give the reaction involved during extraction of zinc from its ore by:

(a) roasting of zinc ore.
(b) calcination of zinc ore.

Q.

Zinc blende ore can be converted into zinc oxide by the process of:
(a) roasting (b) hydrogenation (c) chlorination (d) calcination

Q. Heating of pyrites in the air for oxidation of sulfur is called

1. roasting
2. calcination
3. smelting
4. slagging

Q.

Why should the metal sulphides and carbonates be converted to metal oxides in the process of extraction of metal from them?

Q. The reagent used to leach alumina from bauxite in Bayer's process is:

1. NaOH
2. NaCl
3. HCl
4. KCl

Q. Question 39
Why should the metal sulphides and carbonates be converted to metal oxides in the process of extraction of metal from them?

Q. As a result of roasting, the sulphide ore is converted to metallic form.

1. True
2. False

Q.

Roasting is used to process which of the following ores?

1. Oxide ores

2. Silicate ores

3. Sulphide ores

4. Carbonate ores

Q.

Which of the following reaction is possible

Heating Zinc Oxide with Magnesium or Copper

Q.

A sulphide ore is converted into metal oxide by the process of :
(a) Carbonation (b) roasting (c) calcination (d) anodising

Q.

__ is the process of extraction of metals by electrolysis.

Q.

Which of the following is a use of an electrolytic decomposition reaction?

1. To produce salts

2. They are used in photography

3. To obtain metals from their ores

4. Photosynthesis in plants

Q.

Which of the following term is used to define earthly impurities associated with the ore?

1. Flux

2. Slag

3. Gangue

4. Ores

Q.

Write an equation for the reaction that takes place at the anode during the extraction of aluminium by the electrolytic process?

Q. Roasting is the process of heating a concentrated ore in the excess supply of air.

1. False
2. True

Q. Heating of sulphide ores in the presence of oxygen is termed as ___

Q.

An intimate mixture of ${\mathrm{Fe}}_2{\mathrm{O}}_3$ and aluminium powder is called ___________.

Q.

In the alumino-thermic process, Aluminium acts as

1. An oxidising agent

2. A flux

3. A reducing agent

4. A solder

Q. Zinc blende on roasting in air gives:

1. $ZnC{O}_3$
2. $ZnO$ and $S{O}_2$
3. ZnS and $ZnS{O}_4$
4. $ZnO$ and $C{O}_2$

Q.

Why are Sulphide ores converted to oxide before reduction?

Q. The calcination process is carried out in the absence of ______.

1. sulphur dioxide
2. nitrogen
3. carbon dioxide
4. oxygen

Q. Which of the following ores undergo roasting?

1. $\text{ZnS}$

2. ${\text{CaCO}}_3$

3. ${\text{Cu}}_2\text{S}$
4. ${\text{AgCO}}_3$