Ncert Exemplar Solutions Class 8 Science Materials Metals and Non-Metals

Welcome to NCTB Solutions. Here with this post we are going to help 8th class students for the Solutions of NCERT Exemplar Class 8 Science Book, Unit 4, Materials : Metals and Non-Metals. Here students can easily find step by step solutions of all the problems for Materials : Metals and Non-Metals, Also here our Science teacher’s are solved all the questions with easily understandable language with proper guidance so that all the students can understand easily.

Materials : Metals and Non-Metals Solution :

Multiple Choice Questions :

Question no – (1)

Which of the following is not a metal?

Answer :

Correct option – (b)

Sulphur is not a metal.

Question no – (2)

The substance that will be flattened on beating with a hammer is

Answer :

Correct option – (d)

The substance that will be flattened on beating with a hammer is Zinc granule.

Question no – (3)

Boojho has learnt that non-metals on beating with a hammer are generally broken into pieces. Which of the following is a nonmetal?

Answer :

Correct option – (d)

The piece of coal is a nonmetal.

Question no – (4)

Materials which can be drawn into wires are called ductile. Which of the following is not a ductile material?

Answer :

Correct option – (c)

Sulphur is not a ductile material.

Question no – (5)

Metals are generally hard. Which of the following metals is an exception and can be cut with a knife?

Answer :

Correct option – (b)

Sodium is an exception and can be cut with a knife.

Question no – (6)

Metals are generally solid. Which of the following metals is in the liquid state at room temperature?

Answer :

Correct option – (a)

Mercury is in the liquid state at room temperature.

Question no – (7)

Metals generally react with dilute acids to produce hydrogen gas. Which one of the following metals does not react with dilute hydrochloric acid?

Answer :

Correct option – (d)

Copper does not react with dilute hydrochloric acid,

Question no – (8)

Which of the following reacts with cold water vigorously?

Answer :

Correct option – (b)

Sodium will reacts with cold water vigorously.

Question no – (9)

The metal which produces hydrogen gas on reaction with dilute hydrochloric acid as well as sodium hydroxide solution is

Answer :

Correct option – (c)

The metal which produces hydrogen gas on reaction with dilute hydrochloric acid as well as sodium hydroxide solution is Aluminium.

Question no – (10)

Which of the following non-metals reacts and catches fire on exposure to air?

Answer :

Correct option – (a)

Phosphorus will reacts and catches fire on exposure to air.

Question no – (11)

Generally metallic oxides are basic and non-metallic oxides are acidic in nature. Solution of which of the following oxides in water will change the colour of blue litmus to red?

Answer :

Correct option – (a)

Sulphur dioxide will change the colour of blue litmus to red in water.

Question no – (12)

Which of the following property is not responsible for copper to be used as electrical conduction wires?

Answer :

Correct option – (b)

Colour is not responsible for copper to be used as electrical conduction wires.

Very Short Answer Questions :

Question no – (13)

Answer :

Sodium and potassium are soft and can be easily cut with a knife.

Question no – (14)

Answer :

The Non-metals like hydrogen, nitrogen, carbon, diamond, graphite, chlorine, oxygen sulphur and phosphours are some non-metals which we used in our daily life.

Question no – (15)

Answer :

Nitrogen and Phosphorus are the two non metals that are present in fertilizers and enhances the growth of plants.

Question no – (16)

Answer :

Chlorine is used to disinfect water. Chlorine tablets or bleaching powder is added to the water to disinfect it.

Question no – (17)

Answer :

Iron is a purple coloured non metal which forms a brown solution in alcohol and can be used as an antiseptic to treat wounds on our body.

Question no – (18)

Answer :

We would we unable to spot any changes even after adding some copper turning in zinc sulphate solution. This is because copper is a less reactive than zinc so it couldn’t replace the zinc from the solution and there would be no displacement reactions.

Question no – (19)

Answer :

Bells are made of metals because on bring hit metals are produced a typical sound therefore they are said as sonorous and used for making bells.

Question no – (20)

Answer :

Mercury is used in thermometers because they are found in liquid state even in room temperature.

Question no – (21)

Answer :

Zinc is the most reactive followed by iron and copper. So we could say that zinc will replace the other metals from their salt solutions and iron will be able to replace only copper from its salt solution. Copper would not be able displace other metals at all.

Short Answer Questions :

Question no – (22)

Answer :

Copper often reacts with the atmospheric oxygen, carbon dioxide and water to form a mixture of copper hydroxide and copper carbonate. This mixture gives the copper a greenish appearance. This was the reason why Paheli’s statue turned green after a few months.

Question no – (23)

Answer :

(a) Iron is a metal.

(b) Metals are good Conductors of electricity.

Question no – (24)

Answer :

If we replace the iron nail with a wooden stick the bulb will not glow because woods are very bad conductors of electricity.

Question no – (25)

Answer :

In beaker A iron will displace the copper from the solution forming iron sulphate that is yellowish green in colour along with red mass of copper that will be deposited at the bottom of the beaker. In beaker no such changes will be observed because is less reactive than iron so it will not be able to displace iron from its salt solution.

Question no – (26)

Answer :

The tablets does not looks like an iron metal because the tablet is made up of salts of iron rather that actual metal itself.

Question no – (27)

Answer :

(a) oxygen → (iii) all living beings inhale during breathing.

(b) copper → (iv) for making electric wires.

(c) sulphur → (i) for making crackers.

(d) iron → (v) for making rails.

(e) chlorine → (ii) for disinfecting water.

Long Answer Questions :

Question no – (28)

Answer :

(a) The property of metals by virtue of which they can be drawn into wires is called ductility.

= This statement is correct.

(b) Metals are good conductor of electricity but poor conductor of heat.

= This statement is incorrect

Reason : Because, Metals are good conductors of electricity and heat.

(c) Articles made of metals produce ringing sound when struck hard.

= This statement is Correct.

(d) Oxides of non-metals and metals are acidic in nature.

This statement is incorrect

Reason : Oxides of non metals are acidic in nature but oxides of metals are basic in nature.

(e) A less reactive metal replaces a more reactive metal from its salt solution in water.

This statement is incorrect.

Reason : A more reactive metal replaces a less reactive metal from its salt solution in water.

Question no – (29)

Answer :

It is said that more reactive metals displace the other less reactive metals from its salt solutions. So in order to prove that iron is more reactive than copper we will need to dip a iron nail in Copper Sulphate solution, after leaving it for a while we will see that the colour of the solution changed into green forming ferrous sulphate solution thus proving that iron has displaced the copper in it.

Question no – (30)

Answer :

The name of the product formed in the reaction of sulphur and Oxygen is sulphur dioxide gas. When sulphur dioxide is dissolved in Water, sulphurous acid is formed. The sulphurous acid turns Blue litmus paper to Red. Generally oxides of Non-metals are acidic in nature.

Other Chapter Solutions :

👉 Crop Production and Management

👉 Microorganisms : Friend and Foe

👉 Synthetic Fibres and Plastics

👉 Coal and Petroleum

👉 Combustion and Flame

👉 Conservation of Plants and Animals

👉 Cell-Structure and Functions

👉 Reproduction in Animals

👉 Reaching the Age of Adolescence

👉 Force

👉 Friction