What is an Alloy? - Science and Technology 2


What is an alloy?



An alloy is a homogeneous mixture of two or more metals or of one or more metals with certain non-metallic elements.

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2015-2016 (March)


Give two examples of alloys with their chemical composition.

Tinning : Tin : : Galvanizing : _________

Write two methods of preventing the rusting of iron.

 Which metals do not corrode easily?

Answer the following question.
What are alloys?

Which of the following methods is suitable for preventing an iron frying pan from rusting?

Fill in the blanks in the following statements:

Two methods by which rusting of iron can be prevented are _________ and ____ _

Explain how painting of an iron gate prevents it from rusting.

Explain why rusting of iron objects is faster in coastal areas than in deserts.

Explain why Iron sheets are coated with zinc during galvanization.

Choose the correct answer from the options given below:

Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as

A. Smelting

B. Ore-dressing

C. Calcination

D. Bessemerisation

What is anodising? Give its applications.

Name any three objects (or structures) which are gradually damaged by the corrosion of iron and steel.

Name the metal which is used for galvanising iron.

Explain why, iron sheets are coated with zinc.

Fill in the following blank with suitable word:

The corrosion of copper produces a .............. coating of basic copper carbonate on its surface

Explain why, through aluminium is more reactive than iron, yet there is less corrosion of aluminium when both are exposed to air.

What is corrosion?

What is the corrosion of iron known as?

Explain why, when a copper object remains in damp air for a considerable time, a green coating is formed on its surface. What is this process known as?

A common metal which is highly resistant to corrosion is:
(a) iron
(b) copper
(c) aluminium
(d) magnesium

If copper is kept exposed to damp air for a considerable time, it gets a green coating on its surface. This is due to the formation of:
(a) hydrated copper sulphate
(b) copper oxide
(c) basic copper carbonate
(d) copper nitrate

No chemical reaction takes place when granules of a rusty-brown solid A are mixed with the powder of another solid B. However, when the mixture is heated, a reaction takes place between its components. One of the products C is a metal and settles down in the molten state while the other product D floats over it. It was observed that the reaction is highly exothermic.
(a) What could the solids A and B be?
(b) What are the products C and D most likely to be?
(c) Write the chemical equation for the reaction between A and B leading to the formation of C and D. Mention the physical states of all the reactants and products in this equation and indicate the heat change which takes place.
(d) What is the special name of such a reaction? State one use of such a reaction.
(e) Name any two types of chemical reactions under which the above reaction can be classified.

Four metals P, Q, R and S are all obtained by the reduction of their oxides with carbon. Metal P is used to form a thin layer over the sheets of metal S to prevent its corrosion. Metal Q is used for electroplating tiffin boxes made of metal S whereas metal R is used in making car batteries. Metals Q and R form an alloy called solder. What are metals P, Q, R and S? How have you arrived at this conclusion?

Mention two uses of the following metals and non-metals  


Bronze is an alloy of ______.

Name the metal which is a constituent of Blood pigment ?

Name the metal which is a constituent of plant pigment ?

Explain how the activity series accounts for each of the following:

tendency to corrosion

What is corrosion? What are necessary conditions for corrosion?

State under what conditions corrosion is faster ?

Corrosion can be an advantage in some case.Explain ?

Compare roasting and calcination.

Explain with reason:

Roasting is carried out on sulphide ores and not on carbonate ores?

No chemical reaction takes place when granules of a solid, A, are mixed with the powder of another solid, B. However when the mixture is heated, a reaction takes place between its components. One of the products, C, is a metal and settles down in the molten state while the other product, D, floats over it. It was observed that the reaction is highly exothermic.

(i) Based on the given information make an assumption about A and B and write a chemical equation for the chemical reaction indicating the conditions of reaction, physical state of reactants and products and thermal status of reaction.

(ii) Mention any two types of reactions under which above chemical reaction can be classified.

Complete the process of iron rusting by filling the blanks. Suggest a way to prohibit the process.
The iron rust is formed due to........................... reaction. Different
regions on iron surface become anode and cathode.
 Reaction on anode region :

`F_e(s) → Fe^(2+) (aq) +2e^-`

 Reaction on anode region :

`O_2(g) + 4H^+(aq) +............................ → 2H_2 O (l) `

When Fe2+ ions migrate from anode region they react with ................... to form Fe3+ ions.
A reddish coloured hydrated oxide is formed from ............... ions. It is called rust.

`2Fe_(3+) (aq) + 4H_2O(l) → ................. + 6H_+(aq) `

A way to prevent rusting ..................................................................



Identify the process shown in the diagram and explain it in short

Answer the following question.
a) What is meant by corrosion?
b) Write names of any two methods of prevention of corrosion.
c) In which method, metal like copper, aluminium are coated with a thin layer of their oxides by means of electrolysis.
d) Explain this method with diagram.

Find the odd man out:

What is done to prevent corrosion of metals?

What are the adverse effects of corrosion?

Choose the correct alternative and rewrite the following:

Iron is _____________________.

Answer the following question:
What is corrosion? Do gold ornaments corrode? Justify.

Write three methods of preventing rusting of iron.

Give reasons.

An iron article should be given a coat of paint

Give reasons.

A wooden article should be polished.

Give reasons.

Copper and brass utensils should be tinned.

Explain the term – rusting and give a word equation for the formation of rust. If polished iron nails are kept in three separate test tubes, state the contents in each test tube required, to prove the conditions for rusting.

Give a reason why rust turns moist red litmus blue.

Give reason for the following:

A suspension of rust is basic in nature.

State whether the statement given below is true or false. If false write the correct statement.

Either oxygen or moisture is essential for rusting.

State whether the statement given below is true or false. If false write the correct statement.

Graphite is a lustrous non-metal which conducts electricity.

Write a short note on Alloying.

Observe the following picture and answer the following questions:

  1. What is rust?
  2. Write the chemical formula of rust.
  3. Write the reaction of oxidation of iron at the anode.
  4. Write the reaction of oxidation of iron at the cathode.
  5. What is corrosion?

_______ is an alloy made from iron, carbon and chromium.

When one of the metals in an alloy is mercury the alloy is called _______.

Rusting of iron : Fe2O3 : : corrosion of copper : ______

Find the odd one out and give its explanation.

Write the name.

An alloy of copper and tin-

Write the name.

Method used to prevent corrosion of copper.

Write scientific reason.

On exposure to air, silver articles turn blackish after some time.

Explain concept with example/explain with the help of a balanced equation.


Draw a neat labelled diagram.


Draw a neat labelled diagram.


What is rust?

Write a molecular formula for rust.

Observe the following diagram and give answers.

  1. Name this method of prevention of corrosion.
  2. For prevention of which metal this method is used?
  3. What is used as anode in this method?

Observe the following diagram and write answers.

  1. Name the method.
  2. Explain the method.
  3. Give two examples of this method.

Give preventive methods by giving examples of corrosion?

The process of coating the surface of the metal with a thin layer of zinc is called ______

What is rust?

Give the equation for the formation of rust.

State two conditions necessary for rusting of iron.

Amalgam is an alloy of ____________.

The table shown below gives information about four substances: A, B, C and D.

A 295 Good Good
B 1210 Poor Good
C 1890 Poor Good
D 1160 Poor Poor

Identify Ionic compounds from the above given substances.

Alloys are homogeneous mixtures of a metal with a metal or nonmetal. Which among the following alloys contain non-metal as one of its constituents?

A man painted his main gate made up of iron, to

  1. prevent it from rusting.
  2. protect it from the sun.
  3. make it look beautiful.
  4. make it dust-free.

Which of the above statement(s) is/are correct?

The iron pillar near the Qutub Minar in Delhi is famous for the following facts. Which of these facts is responsible for its long stability?

Galvanisation is a process used to prevent the rusting of which the following?

State whether the following statements are true or false:

Ships suffer a lot of damage though they are painted.

Explain the following:

Lime water turns milky on passing carbon dioxide gas into it.

Explain the following:

Bubbles are produced when acetic acid is added to a solution of sodium hydrogencarbonate. 

Give an example of a chemical reaction for each of the following situations:

Sound is produced

Gold plated ornaments is the example of ______.

Give scientific reasons.

Silver amalgam is used for filling dental cavities.

Explain the chemical reactions in rusting of iron.


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