NCERT Solutions for Class 8 Science Chapter 4 Materials : Metals And Non Metals are provided here with simple step-by-step explanations. These solutions for Materials : Metals And Non Metals are extremely popular among Class 8 students for Science Materials : Metals And Non Metals Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the NCERT Book of Class 8 Science Chapter 4 are provided here for you for free. You will also love the ad-free experience on Meritnation’s NCERT Solutions. All NCERT Solutions for class Class 8 Science are prepared by experts and are 100% accurate.

Page No 18:

Question 1:

Which of the following is not a metal?
(a) copper
(b) sulphur
(c) aluminium
(d) iron 

Answer:

The materials which are hard, lustrous, malleable, ductile, sonorous and good conductors of heat and electricity are called metals. The examples of metals are iron, copper, aluminium, calcium, magnesium, etc. Sulphur is a non-metal because it is soft and dull in appearance. It breaks down into a powdery mass on tapping with a hammer and is not sonorous and a poor conductor of heat and electricity.

Hence, the correct answer is option B.

Page No 18:

Question 2:

The substance that will be flattened on beating with a hammer is
(a) crystal of iodine
(b) lump of sulphur
(c) piece of coal 
(d) zinc granule

Answer:

Malleability is the property of metals by which they can be beaten into thin sheets on beating with a hammer. Zinc is a metal.

Hence, the correct answer is option D.

Page No 18:

Question 3:

Boojho has learnt that non-metals on beating with a hammer are generally broken into pieces. Which of the following is a nonmetal?
(a) iron nail
(b) aluminium wire
(c) copper plate 
(d) piece of coal

Answer:

A piece of coal is generally broken into pieces on beating with a hammer. Therefore, it is a nonmetal.

Hence, the correct answer is option D.

Page No 18:

Question 4:

Materials which can be drawn into wires are called ductile. Which of the following is not a ductile material?
(a) silver
(b) copper
(c) sulphur 
(d) aluminium

Answer:

Ductility is a characteristic property of metals. Sulphur is a nonmetal and therefore, cannot be drawn into wires.

Hence, the correct answer is option C.

Page No 18:

Question 5:

Metals are generally hard. Which of the following metals is an exception and can be cut with a knife?
(a) iron
(b) sodium
(c) gold 
(d) magnesium

Answer:

Sodium is soft and can be cut with a knife.

Hence, the correct answer is option B.

Page No 18:

Question 6:

Metals are generally solid. Which of the following metals is in the liquid state at room temperature?
(a) mercury
(b) silver
(c) aluminium 
(d) sodium

Answer:

Mercury is the only metal which is found in liquid state at room temperature.

Hence, the correct answer is option A.

Page No 18:

Question 7:

Metals generally react with dilute acids to produce hydrogen gas. Which one of the following metals does not react with dilute hydrochloric acid?
(a) magnesium
(b) aluminium
(c) iron 
(d) copper

Answer:

Copper does not react with dilute hydrochloric acid even on heating but it reacts with sulphuric acid.

Hence, the correct answer is option D.



Page No 19:

Question 8:

Which of the following reacts with cold water vigorously?
(a) carbon
(b) sodium
(c) magnesium 
(d) sulphur

Answer:

Sodium metal is very reactive. It reacts vigorously with cold water and a lot of heat is generated in the reaction.

Hence, the correct answer is option B.

Page No 19:

Question 9:

The metal which produces hydrogen gas on reaction with dilute hydrochloric acid as well as sodium hydroxide solution is
(a) copper
(b) iron
(c) aluminium 
(d) sodium

Answer:

Aluminium produces hydrogen gas on reaction with dilute hydrochloric acid as well as sodium hydroxide solution. It is confirmed by a ‘pop’ sound which is produced when a burning match stick is brought near the mouth of the test tube in which reaction takes place.

Hence, the correct answer is option C.

Page No 19:

Question 10:

Which of the following non-metals reacts and catches fire on exposure to air?
(a) phosphorus
(b) nitrogen
(c) sulphur 
(d) hydrogen

Answer:

Phosphorus is a very reactive non-metal and catches fire on exposure to air.

Hence, the correct answer is option A.

Page No 19:

Question 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?
(a) sulphur dioxide
(b) magnesium oxide
(c) iron oxide 
(d) copper oxide

Answer:

Sulphur dioxide is a non-metallic oxide. When it is dissolved in water sulphurous acid is formed.
Sulphur dioxide (SO2) + Water (H2O) → Sulphurous acid (H2SO3)
The sulphurous acid turns blue litmus paper red.

Hence, the correct answer is option A.

Page No 19:

Question 12:

Which of the following property is not responsible for copper to be used as electrical conduction wires?
(a) ductility
(b) colour
(c) good conductor of electricity 
(d) it is solid

Answer:

Copper is used as electrical conduction wires because it is solid, ductile and good conductor of electricity. Colour of copper is not responsible for its use as electrical conduction wires.

Hence, the correct answer is option B.

Page No 19:

Question 13:

Name two soft metals which can be cut with a knife.

Answer:

Sodium and potassium are soft enough to be cut with a knife.

Page No 19:

Question 14:

Which non-metal is essential for our life and all living beings inhale it during breathing?

Answer:

Oxygen is the non-metal is essential for our life and all living beings inhale it during breathing.

Page No 19:

Question 15:

Name two major non-metals which are present in fertilisers and enhance the growth of plants.

Answer:

Nitrogen and phosphorus are the two non-metals which are present in fertilisers and enhance the growth of plants.

Page No 19:

Question 16:

Which non-metal is used to disinfect water?

Answer:

Chlorine is used as a disinfectant to purify water.

Page No 19:

Question 17:

A purple coloured non-metal forms a brown solution in alcohol which is applied on wounds as an antiseptic. Name the nonmetal.

Answer:

Iodine is a purple coloured non-metal which forms a brown solution in alcohol known as Tincture of Iodine. This is applied on wounds as an antiseptic.

Page No 19:

Question 18:

Zinc sulphate forms a colourless solution in water. Will you observe any colour on adding copper turning in it?

Answer:

No colour is observed on adding copper turning in zinc sulphate solution as copper is not able to replace zinc from zinc sulphate solution. This is because copper is less reactive than zinc and less reactive metal cannot replace a more reactive metal.



Page No 20:

Question 19:

Why are bells made of metals?

Answer:

Metals are sonorous i.e. they produce a ringing sound when struck hard. Therefore, bells are made of metals.

Page No 20:

Question 20:

Which liquid metal is used for making thermometers?

Answer:

Mercury is the only metal which is found in liquid state at room temperature. Therefore, it ​is used for making thermometers. The level of mercury rises in accordance with the temperature measured.

Page No 20:

Question 21:

Which of the following metals can displace the other two metals from their salt solutions?
                                                zinc, iron, copper

Answer:

Zinc is more reactive than copper and iron. Therefore, it can displace the other two metals from their salt solutions.

Page No 20:

Question 22:

Paheli bought a statue made of copper. To her surprise it acquired a dull green coating after a couple of months. Explain the reason.

Answer:

Copper statue acquired a dull green coating when exposed to moist air for long time. The green material is a mixture of copper hydroxide (Cu(OH)2) and copper carbonate (CuCO3). The following reaction takes place:
2Cu + H2O + CO2 + O→ Cu(OH)2 + CuCO3

Page No 20:

Question 23:

In Fig 4.1 you find that the bulb glows when an iron nail is placed between two ends of wire. Complete the following sentences on the bases of this fact. 

(a) __________ is a metal.
(b) Metals are good __________ of electricity.

Answer:

(a) Iron is a metal.
(b) Metals are good conductors of electricity.

Page No 20:

Question 24:

 If in Fig. 4.1 iron nail is replaced by a wooden stick, will the bulb glow or not? Justify your answer.

Answer:

No, the bulb will not glow because wooden stick is a non-metal and non-metals are poor conductors of electricity.

Page No 20:

Question 25:

Paheli prepared a blue coloured solution of copper sulphate in beaker A and placed an iron nail in it. Boojho prepared a yellowish green solution of ferrous sulphate in beaker B and placed a copper wire in it. What changes will they observe in the two beakers after an hour?

Answer:

The colour of the solution in beaker A becomes yellowish green due to formation of ferrous sulphate. Also, a reddish brown layer of copper will deposit on the iron nail. This is because iron is more reactive than copper and displaces it from its salt solution.
There will be no change in the colour of the solution in beaker B because copper is less reactive than iron and cannot displace iron from its salt solution.



Page No 21:

Question 26:

A doctor prescribed a tablet to a patient suffering from iron deficiency. The tablet does not look like iron. Explain.

Answer:

The tablet itself is not made of iron metal and hence, does not look like iron. It is made of a salt of iron.

Page No 21:

Question 27:

Match the substances in Column A with their applications given in Column B.

Column A  (Substance) Column B (Application) 
(a) oxygen (i) for making crackers
(b) copper (ii) for disinfecting water 
(c) sulphur (iii) all living beings inhale during breathing
(d) iron (iv) for making electric wires
(e) chlorine (v) for making rails
 

Answer:

Column A  (Substance) Column B (Application
(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 

Page No 21:

Question 28:

Some of the following statements are incorrect. Find the incorrect statements and correct them.
(a) The property of metals by virtue of which they can be drawn into wires is called ductility.
(b) Metals are good conductor of electricity but poor conductor of heat.
(c) Articles made of metals produce ringing sound when struck hard.
(d) Oxides of non-metals and metals are acidic in nature.
(e) A less reactive metal replaces a more reactive metal from its salt solution in water.

Answer:

The incorrect statements are:
(b) Metals are good conductor of electricity but poor conductor of heat.
(d) Oxides of non-metals and metals are acidic in nature.
​(e) A less reactive metal replaces a more reactive metal from its salt solution in water.

The corrected form of incorrect statements are:
(b) Metals are good conductors of heat and electricity.
(d) Oxides of non-metals are acidic in nature while oxides of metals are basic in nature.
​(e) A more reactive metal replaces a less reactive metal from its salt solution in water.

Page No 21:

Question 29:

Iron is more reactive than copper. Can you write an activity to show this?

Answer:

  • Dissolve copper sulphate in about 100 mL water in a beaker. A blue coloured solution is obtained.
  • Put an iron nail into this beaker.
  • Keep the beaker undisturbed for some time.
  • The colour of the solution in beaker becomes yellowish green due to formation of ferrous sulphate. Also, a reddish brown layer of copper will deposit on the iron nail.
  • This is because iron is more reactive than copper and displaces it from its salt solution.

Page No 21:

Question 30:

Fill in the blanks to complete the following paragraph.
The name of the product formed in the reaction of sulphur and _____________ is sulphur dioxide gas.
When sulphur dioxide is dissolved in_________________, sulphurous acid is formed.
The sulphurous acid turns _____________ litmus paper to ____________. Generally oxides of __________ are acidic in nature.
After completing the paragraph write two questions which you can raise on the basis of this information.

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.

Q1. What is the nature of oxides formed by non-metals?
Q2. Which acid is produced on dissolving sulphur dioxide in water?



Page No 22:

Question 31:

Find out the names of three metals and three non-metals from the box given as Fig 4.2.

A X T M S P K L G
X T S U L P H U R
I L R H M N I D L
C I R O N S E J K
A L U M I N I U M
R M U Q T R S T U
B N P C O P P E R
O X Y G E N V W X
N Y Z T A B G H K

Answer:

A X T M S P K L G
X T S U L P H U R
I L R H M N I D L
C I R O N S E J K
A L U M I N I U M
R M U Q T R S T U
B N P C O P P E R
O X Y G E N V W X
N Y Z T A B G H K

Metals: Iron, copper, aluminium
Non-metals: Carbon, sulphur, oxygen
 

Page No 22:

Question 32:

Complete the crossword given in Figure with the help of the clues.

Across
1. Which is generally hard, ductile, malleable and sonorous.
2. A metal is called so it can be drawn into wires.
3. Metal bells are used because of this property.
Down
4. A metal generally used for making jewellery.
5. A metal which is liquid at room temperature.
6. A metal which reacts with acid as well as base to form hydrogen gas.
7. Substances used to enhance the growth of plants.
8. Property by virtue of which metals can be beaten into thin sheets.

Answer:



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