Smelting

Q.

What is smelting

Q.

Define smelting.

Q.

Aluminium is a reactive metal but is still used for packing food articles. Give reason

Q. Match the extraction processes listed in $ColumnI$ with metals listed in $ColumnII$.


$$\begin{array}{cccc}& ColumnI& & ColumnII\\ A.& Self-reduction& p.& Lead\\ B.& Carbonreduction& q.& Silver\\ C.& Complexformationanddisplacementbymetal& r.& Copper\\ D.& Decompositionofiodide& s.& Boron\end{array}$$

1. A. $⟶$ p, r; B. $⟶$ q, s; C. $⟶$ q; D. $⟶$ s.
2. A. $⟶$ p, r; B. $⟶$ p; C. $⟶$ q; D. $⟶$ s.
3. A. $⟶$ p, r; B. $⟶$ s; C. $⟶$ q; D. $⟶$ s.
4. A. $⟶$ r; B. $⟶$ p, s; C. $⟶$ q; D. $⟶$ s.

Q.

Assertion – The non-fusible impurities present in iron ore are removed by $CaC{O}_3$ .

Reason: $CaC{O}_3$ which decomposes into $CaO$ and $C{O}_2$. The $CaO$ formed reacts with $Si{O}_2$ to remove silica

1. Both assertion and reason are correct and the reason is the correct explanation for the assertion.

2. Both assertion and reason are correct but reason is not the correct explanation for the assertion.

3. Assertion is correct but reason is wrong

4. Assertion is incorrect but reason is correct

5. Both assertion and reason are wrong.

Q.

Why silver articles become black after sometime when exposed to air?

Q.

When copper pyrite is roasted in excess of air, a mixture of $C{u}_{2}S$ and $FeO$ are formed. FeO is present as impurity. This can be removed as slag during Smelting. The flux added to form slag is

1. SiO₂ which is a basic flux

2. Limestone, which is a basic flux

3. Silica which is an acidic flux

4. CaO which is a basic flux

Q.

2mg +O gives out 2MgO which is an white precipitate

Here which is the oxidizing agent and which is the reducing agent

Q.

Difference between acids and bases

Q. Native silver metal forms a water-soluble complex with a dilute aqueous solution of NaCN in the presence of:

1. Nitrogen
2. Oxygen
3. Carbon dioxide
4. Argon

Q.

Which of the following is the term used for the fusible product formed when flux reacts with gangue during the extraction of metals?

1. Flux

2. Gangue

3. Slag

4. Ore

Q.

_________ and _______ flames are used for cutting and welding metals.

Q. The methods chiefly used for the extraction of lead and tin from their ores are respectively:

1. Self-reduction and electrolytic reduction

2. Carbon reduction and self-reduction

3. Self-reduction and carbon reduction

4. Cyanide process and carbon reduction

Q. Which of the following is not a basic flux?

1. ${\text{CaCO}}_3$
2. ${\text{Ca(OH)}}_2$
3. ${\text{SiO}}_2$
4. $\text{CaO}$

Q.

is each and every thermite reaction is aluino termite reaction?

Q.

In ___ process, impurities are removed by the addition of flux as slag.

Q.

Extraction of which metal from their ores require carbon? Name all of them.

Q. 5. Slaking of lime is (i) An endothermic reaction (ii) An exothermic reaction (iii) A combination reaction (iv) A decomposition reaction. A) (i) & (iii) B) (i) & (iv) C) (ii) & (iii) D) (ii) & (iv) 6. The oxidation number of sulphur in sulphuric acid is A) 2 B) 4 C) 3 D) 6 7. A copper vessel acquires a green coloured coating when kept in moist air for a few days. The green coloured subs†an ce is chemically A) Acidic copper oxide B) Basic copper sulphate C) Hydrated copper sulphate D) Basic copper carbonate.

Q. 1) How can you protect the following from rusting? [2 MARKS]
(a) Iron mug
(b) An iron spoon
(c) Bicycle handle
(d) Bicycle chain

2) Write a short note on the electronic nature of non-metals? [3 MARKS]

Q.

Give one word to the following:

A process of extracting metals from its ores by electrolysis.

Q.

Smelting is used to extract base metals from oxides.

1. True

2. False

Q. If silica is present as an impurity in an ore, then which of the following can be used as flux?

1. Water
2. Calcium oxide
3. Sulphur dioxide
4. Carbon dioxide

Q.

What is metallurgy

Q.

State the principle for each of the following processes which are used in metallurgy in general.
(i) Roasting
(ii) Gravity separation
(iii) Froth flotation
(iv) Aluminothermy
(v) Calcination
(vi) Electromagnetic separation.

Q. Tin is extracted from its ore, cassiterite, by :

1. Carbon reduction
2. Electrolytic reduction
3. The aluminothermic process
4. Carbon-monoxide reduction

Q. Which metal is called strategic metal?

Q. Find the number of metals which are commercially reduced by carbon reduction method from the given metals:
Ag, Cr, Mn, Sn, Zn, Fe

Q. $2PbS+3O_2⟶A+2S{O}_2$
The name of A is :

1. sesquioxide
2. none of these
3. galena
4. Iitharge

Q. Carbon reduction is not used to obtain certain metals from their ores because
1. Carbon cannot reduce certain oxides, sulphides, etc
2. It can react with the metals to form carbides
3. Temperatures required for the reduction are too high
4. It is expensive compared to the alternatives for some ores

Q. Choose the correct code regarding the roasting process:
(I) It is the process of heating ore in air to obtain the oxide

1. I, II and III
2. I, II, and IV
3. II, III, and IV
4. I, II, III, and IV