Calcination

Q.

When ferrous sulphate is added to a solution of potassium permanganate, it turns colourless. Why?

Q.

Define calcination and roasting. Give one example of each?

Q.

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

Q. Which method do you suggest for extraction of highly reactive metals and why?

Q.

Why should magnesium ribbon be cleaned before burning in air?

Is it because it reacts with CO₂ or with O₂ in the air?

Q.

What is Calcination Gypsum?

Q.

For which of the following ores calcination process cannot be used?

1. $CaC{O}_3$

2. $A{l}_2{O}_3.2H_{2}O$

3. $ZnS$

4. $CaC{O}_3.Ca(OH{)}_2$

Q.

The chemical is added to reduce the melting point of the reaction mixture during the extraction of aluminum is

1. Cryolite

2. Calamine

3. Kaolite

4. Bauxite

Q.

How can iron be extracted from haematite ore?

Q.

Which of the following method is used to extract metals from their carbonate ores?

1. Hydrolysis

2. Calcination

3. Roasting

4. Electrolysis

Q. The process in which carbonate ores are changed into oxides by heating strongly in absence of air, is:

1. Smelting
2. Roasting
3. Calcination
4. Levigation

Q.

How is zinc extracted from its ore

Q. Question 14

In the refining of silver, the recovery of silver from silver nitrate solution involves displacement by copper metal. Write down the reaction involved.

Q.

In the calcination process, the ore is heated in

1. the absence of oxygen.

2. excess oxygen.

3. the absence of nitrogen.

4. the absence of air.

Q. Why we use calcination for carbonates but roasting for sulphides?

Q.

Name the method used to obtain lead from its ore galena (lead sulphide).

1. Electrolytic refining

2. Electrolytic reduction

3. Roasting

4. Calcination

Q.

How can Zinc metal be extracted from Zinc oxide ore? Suggest a chemical reaction and explain the key concept involved in the process.

Q.

Question 49
What happens when?

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

Q. Which of the following processes is unsuitable for softening water possessing temporary hardness?

1. Adding calcium hydroxide
2. Boiling
3. Distillation
4. Filtration

Q.

Carbonate ores are reduced by the process of:

1. Calcination

2. Roasting

3. Heating

4. Distillation

Q.

'In the process of reduction of concentrated ore to zinc spelter, ZnO is made into briquettes.' Give reasons.

Q.

Which of the following is true for calcination of a metal ore?

1. It makes the ore more porous

2. The ore is heated to a temperature when fusion just begins.

3. Hydrated salts lose their water of crystallization

4. Impurities of S, As and Sb are removed in the form of their volatile oxide.

Q. Which of the following ores is converted into metal oxide by calcination?

1. 
   Galena
2. 
   Cinnabar
3. 
   Chalcocite
4. 
   Calamine

Q. Zinc carbonate ore is converted into zinc oxide ore by the process called:

1. roasting
2. calcination
3. electrolysis
4. anodising

Q.

Which process is used to reduce roasted metallic oxide to metal in molten conditions?

1. Roasting

2. Calcination

3. Electrolysis

4. Smelting

Q.

The process in which ores are changed into oxides by heating strongly in limited air is known as:

1. Galvanisation

2. Roasting

3. Calcination

4. Electrolytic refining

Q.

Name an ore of zinc other than zinc oxide. Also, name the process by which this ore can be converted into zinc oxide? [2 MARKS]

Q.

(a) Name the methods by which concentrated ore is converted to metallic oxide.

(b) State three objectives achieved during the roasting of ores.

Q.

State whether the following statement is true or false.

"Carbonate ores get changed into oxides by heating strongly in limited air. This process is known as calcination."

1. True

2. False

Q.

How are ores concentrated? Is it different for sulphide and carbonate ores?