NCERT Exemplar Solutions Class 8 Science Materials Metals and Non Metals

Read NCERT Exemplar Solutions Class 8 Science Materials Metals and Non Metals below, students should study NCERT Exemplar class 8 Science available on Studiestoday.com with solved questions and answers. These chapter wise answers for class 8 Science Exemplar problems have been prepared by teacher of Grade 8. These NCERT Exemplar class 8 Science solutions have been designed as per the latest NCERT syllabus for class 8 and if practiced thoroughly can help you to score good marks in standard 8 Science class tests and examinations

 

Multiple Choice Questions.......................


Question 1:  Which of the following is not a metal?

(a) Copper

(b) Sulphur

(c) Aluminium

(d) Iron 

Solution 1:  (b) Sulphur

Copper, Aluminium and Iron are metal but Sulphur is a non metal.

 

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 

Solution 2: (d) Zinc granule

Metals can be beaten into thin sheets while non-metals shatter when struck, so the correct option is i.e. (d) Zinc granule.

 

Question 3: Boojho has learnt that non-metals on beating with a hammer are generally broken into pieces. Which of the following is a non-metal?

(a) Iron nail

(b) Aluminium wire

(c) Copperplate

(d) Piece of coal 

Solution 3: (d) Piece of coal

Iron, copper, and aluminium are metals, and coal is a non-metal, so the correct option is (d) piece of coal.

 

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 

Solution 4: (c) Sulphur

Metals have a property called ductility. Sulphur is a non-metal that has no ductile properties. 

 

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 

Solution 5: (b) Sodium 

Sodium is a highly reactive metal that appears soft and can be cut up with a knife.

 

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 

Solution 6: (a) Mercury

Metals are generally found in solid state but there are some exceptions like mercury is liquid in state at room temperature.

 

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 

Solution 7: (d) Copper

Copper, gold, and silver are less reactive metals that do not contain hydrogen gas when exposed to dilute HCl.

 

Question 8: Which of the following reacts with cold water vigorously?

(a) Carbon

(b) Sodium

(c) Magnesium

(d) Sulphur 

Solution 8: (b) Sodium

Since sodium reacts violently with water, it is contained in kerosene to prevent reaction with atmospheric moisture and oxygen. 

 

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 

Solution 9: (c) Aluminium

Aluminium produces hydrogen gas when it reacts with dilute HCl or NaOH.

 

Question 10: Which of the following non-metals reacts and catches fire on exposure to air?

(a) Phosphorus

(b) Nitrogen

(c) Sulphur

(d) Hydrogen 

Solution 10: (a) Phosphorus

Phosphorus is a non-metal which reacts and catches fire on exposure to air.

 

Question 11:  Generally, metallic oxides are basic and non-metallic oxides are acidic in nature. The 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 

Solution 11: (a) Sulphur dioxide

Sulphur can be used in a number of ways. Blue litmus can turn red when exposed to sulphur-dioxide, which is acidic in nature.

 

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 

Solution 12: (b) Colour

Due to the ductility, good conductor of electricity and solid state, copper is used as electrical conduction wires. 

 

Very Short Answer Questions..................


Question 13: Name two soft metals which can be cut with a knife. 

Solution 13:  Two soft metals which can be cut with a knife are: 

(i) Sodium

(ii) Potassium

 

Question 14:  Which non-metal is essential for our life and all living beings inhale it during breathing? 

Solution 14:   Oxygen is essential for our life and all living beings inhale it during breathing.

 

Question 15:  Name two major non-metals which are present in fertilisers and enhance the growth of plants. 

Solution 15:   Two major non-metals which are present in fertilisers and enhance the growth of plants are: 

(i)Nitrogen

(ii) Phosphorus

 

Question 16:  Which non-metal is used to disinfect water? 

Solution 16:   Chlorine is used to disinfect water as it has the ability to kill the germs.

 

Question 17:  A purple coloured non-metal form a brown solution in alcohol which is applied on wounds as an antiseptic. Name the non-metal. 

Solution 17:   Iodine is a purple coloured non-metal form a brown solution in alcohol which is applied on wounds as an antiseptic.

 

Question 18:  Zinc sulphate forms a colourless solution in water. Will you observe any colour on adding copper turning in it? 

Solution 18:   Zinc sulphate forms a colourless solution in water. On adding copper there will be no change as displacement reaction will not take place.

 

Question 19:  Why are bells made of metals? 

Solution 19:   Metals show the sonorous property, hence they are used in making bells.

 

Question 20:  Which liquid metal is used for making thermometers? 

Solution 20:   Mercury is liquid metal used for making thermometers.

 

Question 21:  Which of the following metals can displace the other two metals from their salt solutions?

Zinc, Iron, Copper 

Solution 21:  Zinc has the tendency to react more rather than the others given in the question. Zinc is more reactive while Iron and copper are less reactive. Zinc can displace the other two metals from their salt solutions.

 

Short Answer Questions..................


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. 

Solution 22:   When a copper statue is exposed to wet air for an extended period of time, it develops a dull green coating. The green substance is a mixture of copper hydroxide [Cu(OH)z] and copper carbonate (CuC03), which is formed when copper reacts with moist air. The reaction is as follows.

 NCERT Exemplar Solutions Class 8 Science Materials Metals and Non Metals

 

Question 23:  In the Figure given below you find that the bulb glows when an iron nail is placed between two ends of the wire. Complete the following sentences on the bases of this fact.

 NCERT Exemplar Solutions Class 8 Science Materials Metals and Non Metals

(a) __________ is a metal.

(b) Metals are good __________ of electricity. 

Solution 23:

a) Iron is a metal.

b) Metals are good conductors of electricity.

 

Question 24:  If in the figure given below iron nail is replaced by a wooden stick, will the bulb glow or not? Justify your answer.

NCERT Exemplar Solutions Class 8 Science Materials Metals and Non Metals

Solution 24:  No, the bulb will not glow If the iron nail is replaced by a wooden stick as the wood is bad conductor of electricity.

 

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? 

Solution 25:  A reddish-brown coating of copper will form on the iron nail in beaker A, and the blue solution will turn yellowish-green. Beaker B, on the other hand, shows no signs of change.

 

Question 26:  A doctor prescribed a tablet to a patient suffering from iron deficiency. The tablet does not look like iron. Explain. 

Solution 26:   While iron is a metal, the tablet is not made of it. It is made up of an iron salt. As a result, it does not seem to be iron.

 

Question 27:  Match the substances in Column A with their applications given in Column B.

NCERT Exemplar Solutions Class 8 Science Materials Metals and Non Metals

Solution 27:

NCERT Exemplar Solutions Class 8 Science Materials Metals and Non Metals

 

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. 

Solution 28:

(a) Correct

(b) Incorrect- Metals are excellent heat and electricity conductors.

(c) Correct

(d) Incorrect- The oxides of non-metals are acidic, while the oxides of metals are basic.

(e) Incorrect- In water, a more reactive metal evicts a less reactive metal from its salt solution.

 

Question 29:  Iron is more reactive than copper. Can you write an activity to show this? 

Solution 29:   Take Separate copper sulphate and iron sulphate solutions in test tubes.

Take Copper nail and iron nail.

Place the copper wire in an iron sulphate solution and the iron nail in a copper sulphate solution.

NCERT Exemplar Solutions Class 8 Science Materials Metals and Non Metals

A reaction is observed in a test tube containing an iron nail and a copper sulphate solution. Sulphate is taken away from copper by iron. You will see that a reaction occurs, and copper is left alone. We may now assume that copper sulphate has been replaced by iron. 

Copper sulphate + Iron———► Iron sulphate + Copper                       

The more reactive metal displaces the less reactive metal in such a reaction. As a result of the preceding activity, iron is more reactive than copper.

 

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. 

Solution 30:  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. After completing the paragraph write two questions which you can raise on the basis of this information. 

  1. Which gas is formed when sulphur reacts with oxygen?

       2.    If sulphur dioxide is dissolved in water, what happens?  


Question 31:  Find out the names of three metals and three non-metals from the box given in figure.

NCERT Exemplar Solutions Class 8 Science Materials Metals and Non Metals

Solution 31:

NCERT Exemplar Solutions Class 8 Science Materials Metals and Non Metals


Question 32:  Complete the crossword given in figure with the help of the clues.

NCERT Exemplar Solutions Class 8 Science Materials Metals and Non Metals

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. 

Solution 32:

NCERT Exemplar Solutions Class 8 Science Materials Metals and Non Metals