Lakhmir Singh solutions for Chemistry [English] Class 10 ICSE chapter 7 - Metallurgy [null edition]

State whether the following statement is True or False.

Metals are found in the reduced form in the combined state.

State whether the following statement is True or False.

Bauxite is an ore of aluminium.

State whether the following statement is True or False.

The removal of unwanted impurities from the ore is called ore dressing.

State whether the following statement is True or False.

Hydrolytic method is used for the concentration of sulphides ores.

______ and ______ metals occur in a free state as well as in the combined state.

The minerals from which the metals can be conveniently and profitably extracted are called ______.

The ores of iron are ______ and ______.

The ______ method is based on the principle of differences in the densities of ore and gangue.

Which of the following is an ore of copper?

The method based on the preferential wetting of sulphides ores by oil and gangue by water is ______.

The method used for extracting precious metals is ______.

Name the important ores of zinc.

Write the name and formula of two ores of the following:

Iron

Define the term : Ore

What is the difference between a mineral and an ore?

Define the term slag with examples of acidic and basic fluxes.

Give the principles of the hydrolytic method.

Give the principles of electromagnetic separation.

Give the principles of the froth floatation process.

Explain the chemical method for the extraction of metal with examples.

State whether the following statement is True or False.

Roasting is the process of converting an ore into its oxide by heating strongly at a temperature below its melting point in excess of air.

State whether the following statement is True or False.

Aluminium metal is extracted by the electrolysis of its molten oxide.

State whether the following statement is True or False.

Liquation process is employed when the impurity is less fusible than metal itself.

______ process is commonly used for carbonate ores.

The arrangement of metals in decreasing order of their reactivity is called ______.

The ore of iron is reduced in blast furnace by using ______ and ______.

Lead is obtained by reduction of their oxides with:

Which of the following method is used to purify mercury, zinc and cadmium?

Which of the following is purified by electrorefining?

Define roasting.

Define calcination.

Write a note on the extraction of highly reactive metals.

Define the process of liquation with examples.

Give the basis for the purification of metal by distillation.

Give the basis for the purification of metal by oxidation.

Explain electrorefining with a labelled diagram.

State whether the following statement is True or False.

Magnetite is an ore of aluminium.

State whether the following statement is True or False.

Pure alumina is obtained from bauxite ore by Baeyer’s process.

State whether the following statement is True or False.

Aluminium is malleable but not ductile.

State whether the following statement is True or False.

Pure aluminium is corroded by pure water.

State whether the following statement is True or False.

A thermite is a mixture of 3 parts of ferric oxide and 1 part of aluminium powder.

Aluminium was discovered by ______.

______ contains 60% Al₂O₃ and rest being sand, ferric and titanium oxide.

The bottom layer of the electrolytic cell during refining of aluminium is formed by ______ aluminium.

Aluminium is a powerful ______ agent.

Aluminium is used in ______ as it is light strong and corrosion resistant.

Which of the following is an ore of aluminium?

Red mud consists of ferric oxide, sand which are removed by ______.

Which of the following alloys does not contain copper?

Brass is an alloy of ______.

Write the chemical formulae of the main ore of aluminium.

Write the chemical formulae of the main ore of iron.

Give the chemical names and formulae of the main ores of zinc.

Complete the following reaction:

\[\ce{Al2O3 + 2NaOH + 3H2O ->[473 - 923 K]}\]

Complete the following reaction:

______ \[\ce{->[Heat][1473 K] Al2O3 + 3H2O}\]

Complete the following reaction:

______ \[\ce{+ 2H2O -> NaOH + Al(OH)3 ↓}\]

Write the electrode reactions involved in Hall-Heroult’s process.

Write the action of air, water, acids, bases and non metals on aluminium.

State two important uses of following metals: 

Uses of iron   

Give the uses of zinc.

Define:

Alloy

State two important uses of the following metal. 

Uses of magnesium  

Write the uses of invar.

Write the uses of gun metal.

Manufacturing of a car requires special consideration of its overall weight. More weight of the car means more consumption of fuel during the driving. Hence, engineers are always in search of such an alloy that can be used to reduce the overall weight of a car without compromising on the strength of components and hence the safety of the passengers.

Considering the scenario discussed above, suggest which type of alloy might be suitable for the automobile industry? Also, do research, using the internet, to find out what kind of metals or alloys automobile companies are using currently to manufacture cars.

True or False.

Cinnabar is an ore of mercury.

True or False.

Hydrolytic method is also known as gravity separation.

True or False.

Leaching is based on the principle of preferential wetting of sulphide ores by oil and gangue by water.

True or False.

Carbon is placed just below zinc in the reactivity series.

True or False.

In electrorefining, impure metal is made the cathode.

______ is the fusible product formed when flux combines with impurities during extraction of metals.

Ores are broken into small pieces and then reduced to fine powder. The process is called ______.

The oxide ores of ______ and ______ are usually concentrated by levigation.

Roasting is carried out either in a ______ furnace or in a ______ furnace.

Aluminium decomposes boiling water, evolving ______.

The alloy of iron, stainless steel is used for making ______ and ______.

Which of the following process is used to concentrate chromium ore?

In the following reaction,

\[\ce{CaCO3 ->[Heat] A + B}\]

A and B are respectively,

Which of the following makes the ore porous and more reactive?

The formula of calamine ore is ______.

Which of the following are added to purified alumina?

The electrolyte used in Hall and Heroult process is:

Aluminium is ______.

The process by which sulphur is removed from sulphide ores by heating is called ______.

Solder is an alloy of ______.

Duralumin is an alloy of ______.

Which of the following alloys of iron is tough, hard and durable?

Match the column I with column II and choose the correct option.

The ore of aluminium is ______.

Define the term:

Flux

Define the term: 

Slag

What is meant by concentration of ores?

Explain the method of extraction by froth floatation.

Give the examples for the extraction of metal by leaching.

Write a note on the extraction of highly reactive metals.

Write the different reactions that occur in a blast furnace.

Complete the following reaction:

\[\ce{2Cu2S + 3O2 ->[Roasting]}\] ______ + ______

Complete the following reaction:

\[\ce{2Cu2O + Cu2S ->[\Delta]}\] ______ + ______

Define the oxidation process of refining of metal.

Write the chemical name and formula of the following ore.

Iron pyrites

Write the chemical name and formula of the following ore.

Bauxite

Define two chemical properties of aluminium.

Give the uses of aluminium as having a strong affinity for oxygen.

Give the uses of aluminium as a good conductor of electricity.

Define:

Alloy

Give the uses of duralumin.

Name the main constituent metal in the following alloys:

Duralumin

Name of the main constituent metal in the following alloy.

Brass

Name the main constituent metal in the following alloy:
Stainless steel

The following questions are relevant to the extraction of Aluminium:

1. State the reason for the addition of caustic alkali to bauxite ore during the purification of bauxite.
2. Give a balanced chemical equation for the above reaction.
3. Along with cryolite and alumina, another substance is added to the electrolyte mixture. Name the substance and give one reason for the addition.

State the main components of the following alloy:

Brass

State the main components of the following alloy:

Duralumin

State the main components of the following alloy:

Bronze

Name the following:

The property possessed by metals by which they can be beaten into sheets.

Name the following:

A compound which is added to lower the fusion temperature of the electrolytic bath in the extraction of aluminium.

Name the following:

The ore of zinc containing its sulphide.

Answer the following questions with respect to the electrolytic process in the extraction of aluminium:

Identify the components of the electrolyte other than pure alumina and the role played by each.

Answer the following question with respect to the electrolytic process in the extraction of aluminium:

Explain why powdered coke is sprinkled over the electrolytic mixture.

Name the following :
The process of coating of iron with zinc.

Name the following :
An alloy of lead and tin that is use in electrical circuits.

Name the following :  
An ore of zinc containing its sulphide.

Name the following :
A metal oxide that can be reduced by hydrogen

For the electro-refining of copper:

1. What is the cathode made up of?
2. Write the reaction that takes place at the anode.

Name the main component of the following alloy:

Brass

Name the main constituent metal in the following alloys:

Duralumin

State the main components of the following alloy:

Bronze

Name the most common ore of the metal aluminium from which the metal is extracted. Write the chemical formula of the ore.

Name the process by which impure ore of aluminum gets purified by using concentrated solution of an alkali.

Write the equation for the formation of aluminum at the cathode during the electrolysis of alumina.

 Give the chemical formula of : 
Bauxite 

Give the chemical formula of :
 Cryolite 

Give the chemical formula of : 
 Sodium aluminate 

 Answer the following questions based on the extraction of aluminium from alumina by Hall - Heroult’s Process : 
What is the function of cryolite used along with alumina as the electrolyte? 

Answer the following questions based on the extraction of aluminium from alumina by Hall - Heroult’s Process : 
Why is powdered coke sprinkled on top of the electrolyte? 

Answer the following questions based on the extraction of aluminium from alumina by Hall - Heroult’s Process : 
Name the electrode, from which aluminium collected.  

 Match the alloys given in column I to the uses given in column II : 

Baeyer’s process is used to concentrate bauxite ore to alumina.

Give balanced chemical equation for the reaction taking place for its conversion from bauxite ore to alumina.

Give a reason for the following.

Oxides of highly reactive metals are very stable and cannot be reduced by common reducing agent.

Give a reason for the following.

During Hall-Heroult’s process, powdered coke is sprinkled over the surface of electrolyte.

Give a reason for the following.

The reaction of aluminium with HCl is slow in the beginning.

Distinguish between:

Froth floatation - Leaching

What is the difference between calcination and roasting?

Differentiate between the following:

Distillation and liquation

Differentiate between the following:

Invar and Alnico

Give the principle and examples of the following.

Hydrolytic method

Give the principle and examples of the following.

Magnetic separation

Give the principle and examples of the following.

Froth floatation

Give the principle and examples of the following.

Leaching

Write a note on the extraction of moderately reactive metals.

Write a note on the extraction of less reactive metals.

Define the term refining.

Explain electrorefining with a labelled diagram.

Explain Bayer’s process.

Explain the following process:

Hall-Heroult’s process

Explain the action of the following on aluminium:

Acids

Explain the action of the following on aluminium:

Bases

Explain the action of the following on aluminium:

Non-metals

What is the action of water on aluminium? Write the equation of the chemical reaction involved.

Explain the action of the following on aluminium:

Air

Define:

Alloy

What is the purpose of making alloys?

Write the methods of making alloys.

Name a metal which is found abundantly in the Earth's crust.

What is the difference between calcination and roasting?

Name the process used for the enrichment of sulphide ore.

Write the chemical formulae of the main ore of iron.

Write the chemical formulae of the main ore of aluminium.

Write the constituents of the electrolyte for the extraction of aluminium.

Match the properties and uses of alloys in List 1 with the appropriate answer from List 2:

For the substance given below, describe the role played in the extraction of aluminium.

Cryolite

For the substance given below, describe the role played in the extraction of aluminium.

Sodium hydroxide

For the substance given below, describe the role played in the extraction of aluminium.

Graphite

Explain why : 
In the electrolysis of alumina using the Hall Heroult's Process the electrolyte is covered with powdered coke.

Explain why :
Iron sheets are coated with zinc during galvanization.

Name the solution used to react with bauxite as a first step in obtaining pure aluminium oxide, in the Baeyer's process.

Write the equation for the reaction where the aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide.

Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.

Write the equation for the reaction that occurs at the cathode during the extraction by aluminium by electrolysis.

Explain why it is preferably to use a number of graphite electrodes as anode instead of a single electrode, during the above electrolysis.