Explore topic-wise InterviewSolutions in .

1. Dressing or concentration. 

2. Extraction of crude metal. 

3. Refining or purification of the metal.

Flux: Flux is a substance added to the ore to remove the gangue from it by reacting with ore.

Distillation is very useful for the purification of low boiling metals like zinc and mercury containing high boiling metals as impurities.

Correct option is  D) Blast

Correct Answer is  B) Slag

Correct option is  C) Fire box

We add some suitable impurities to ore in order to decrease its melting point.

Froth flotation method is suitable to enrich sulphide ores.

Furnace: Furnace ¡s the one which is used to carry out pyrochemical processes in metallurgy.

These metals are generally sulphides and carbonates. They are converted into oxides before reducing them to metals.

Arrangement of the metals in decreasing order of their reactivity is known as activity series

Highlyreactive metals can be extracted by electrolysis of their fused compounds.

B) coke, lime stone

The coke is used as fuel and limestone (CaCO₃) is used as flux for haematite ore.

C) (i), (ii) and (iii)

PVC pipes do not rust. So they are used as water pipes instead of metal.

The method of reduction which is useful for chloride of magnesium which is active is electrolytic reduction. 

Fused MgCl₂ is electrolysed with steel cathode (-) and graphite anode (+). The metal (Mg) will be deposited at cathode and chlorine gas liberates at the anode.

At cathode : Mg²⁺ + 2 e^- → Mg

At anode : 2 Cl^- → Cl₂ + 2e^-

Correct option is  B) Aluminium

1. The metals like zinc, iron, lead are moderately reactive. 

2. They are found in the earth’s crust mainly as oxides, sulphides and carbonates.

Furnace : 

Furnace is the one which is used to cany out pyrochemical processes in metallurgy

Furnace has mainly three parts : 

1) Hearth: Hearth is the place inside the furnace where the ore is kept for heating. 

2) Chimney: Chimney is the outlet through which flue (waste) gases go out of the furnace. 

3) Fire box: Fire box is the part of the furnace where the fuel is kept for burning.

The process of removal of impurities from an ore is called dressing of the ore or concentration of the ore.

Limestone or calcium carbonate (CaCO₃).

Methods which produce very pure metals are : 

1. Electrolytic Reduction 

2. Smelting. 

(OR) 

1. Distillation 

2. Poling.

Ag < Fe < Zn < Na 

(OR) 

Ag, Fe, Zn, Na

Correct option is : d) Electrolysis

It is the process of heating the concentrated ore in the absence of air

a) Annapurna salt : Iodine, chlorine – Non-metals 

b) Liquid used in thermometer : Mercury – Metal 

c) Lead of the pencil : Graphite – Nonmetal 

d) Chlorophyll : Magnesium – Metal 

e) Filament in electric bulb : Tungsten – Metal 

f) Enamel layer on teeth : Calcium phosphate – Non-metal

When sulphide ore of copper is partially roasted, the rest of the sulphide ore reacts with oxide and forms the metal. This is called auto reduction.

Iron and copper.

The impurity present in the ore is called gangue. The substance added to the ore to remove gangue from it is called flux.

Concentration or Dressing: concentration is the removal of the unwanted rocky material as possible before the ore is being converted into metal.

1) Burning of ore in the presence of air or oxygen is called “Roasting”. So in the roasting air is present. 

2) Burning of ore in the absence of air or oxygen is called “Calcination.” So in the calcination air is absent.

Human history in terms of materials had the Bronze age and Iron age. Pertaining to metals, they started to use bronze and iron.

a) Electrolytic reduction. 

b) Smelting.

B) oxidation process

Corrosion occurs due to reaction of metal with both air and water

Furnace is used to carry out pyrochemical process in metallurgy.

Various types of furnaces : 

1) Blast furnace: Blast furnace has both fire box and hearth combined in big chamber which accommodates both ore and fuel. 

2) Reverberatory furnace : It has both fire box and hearth separated, but the vapours (flame) obtained due to burning of the fuel touch the ore in the hearth and heat it. 

3) Retort furnace : In this furnace there is no direct contact between the hearth or fire box and even the flames do not touch the ore.

Auto (self) reduction: When sulphide ore of copper is partially roasted it gives oxide when the supply of air is stopped, the rest of sulphide reacts with oxide and forms the metal and SO₂ is called auto reduction.

Jewellery, conducting wires and utensils.

By painting, oiling and greasing, etc.

1. Covering the surface of iron materials with paint or by some chemicals. 

2. Electroplating.

To make iron hard and strong.

Displacement reactions: The reaction in which a more active metal displaces less active metal from its compound is called displacement reaction.

Prevention of corrosion of metals : 

1. Covering the surface of metal with paint or by some chemicals like bisphenol which prevent the surface of metallic object to come in contact with atmosphere.

2. Covering the surface of metal by other metals like tin or zinc that are inert or react themselves with atmosphere to save the metal. 

3. An electrochemical method in which a sacrificial electrode of another metal like magnesium and zinc, etc. corrodes itself to save the metal.

The main impurity that can be removed is slag because it is formed when gangue in the ore reacts with flux.

CaO + SiO₂ → CaSiO₃

The essential condition that iron articles get rust is presence of water and air both.

Iron articles get rust due to both air and water.

B) Hydrated ferric oxide