Metals and Non-Metals - Cbse Ncert Solutions of Class 10 Science Chapter 3 InText Questions

 

Metals and Non-metals

Class X, NCERT Solutions of Chapter 3 Science InText Questions


CBSE NCERT Solutions: InText Questions (Page 40)
Question 1: Give an example of a metal which
(i) is a liquid at room temperature.
(ii) can be easily cut with a knife.
(iii) is the best conductor of heat.
(iv) is a poor conductor of heat.
Answer: (i) Mercury.  (ii) Sodium.  (iii) Silver.  (iv) Lead and Mercury.

Question 2: Explain the meanings of malleable and ductile.
Answer:
Malleable: Some metals can be beaten into thin sheets. This property is called malleability and such substances are called malleable. For example gold, silver.
Ductile: Substances that can be drawn into thin wires are called ductile. Most of the metals are ductile.

CBSE NCERT Solutions: InText Questions (Page 46)
Question 3: Why is sodium kept immersed in kerosene oil?
Answer: Sodium is highly reactive on exposure to air at room temperature. It reacts with oxygen and catches fire. It also reacts with water. But, it neither reacts nor dissolves in kerosene. So, in order to protect it sodium is kept under kerosene.

Question 4: Write equations for the reactions of
(i) Iron with steam
(ii) Calcium and potassium with water
Answer:  
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Question 5: Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows:
Metal
Iron (II) sulphate
Copper (II) sulphate
Zinc sulphate
Silver nitrate
A
No reaction
Displacement


B
Displacement

No reaction

C
No reaction
No reaction
No reaction
Displacement
D
No reaction
No reaction
No reaction
No reaction

Use the Table above to answer the following questions about metals A, B, C and D.
(i) Which is the most reactive metal?
(ii) What would you observe if B is added to a solution of Copper (II) sulphate?
(iii) Arrange the metals A, B, C and D in the order of decreasing reactivity.
Answer:  From the above table we obtain the reactivity series as follows:
Zn > B > Fe > A > Cu > C > Ag > D
(i) Metal B is the most reactive metal.
(ii) Displacement reaction.
(iii) Metal B > Metal A > Metal C > Metal D.

Question 6: Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4.
Answer: Hydrogen gas is evolved along with salt of the metal. Equation for the chemical reaction that will take place between iron and dil. H2SO4 is -
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Question 7: What would you observe when zinc is added to a solution of iron(II) sulphate? Write the chemical reaction that takes place.
Answer:  Since, zinc is more reactive than iron. So, it will displace iron from iron(II) sulphate. The equation will be as follows:
https://www.cbsencertsolution.com/2019/02/metals-and-non-metals-cbse-ncert-solutions-of-class-10-science-chapter-3-intext.html



CBSE NCERT Solutions: InText Questions (Page 49)
Question 8: (i) Write the electron-dot structures for sodium, oxygen and magnesium.
(ii) Show the formation of Na2O and MgO by transfer of electrons.
(iii) What are the ions present in these compounds?
Answer: (i)
https://www.cbsencertsolution.com












(ii)
https://www.cbsencertsolution.com/2019/02/metals-and-non-metals-cbse-ncert-solutions-of-class-10-science-chapter-3-intext.html













(iii)
https://www.cbsencertsolution.com/2019/02/metals-and-non-metals-cbse-ncert-solutions-of-class-10-science-chapter-3-intext.html




Question 9: Why do Ionic compounds have high melting points?
Answer: The molecules of Ionic compounds are bounded by strong electrostatic force of attraction between the ions. Hence, it requires a lot of energy to overcome these forces and so Ionic compounds have high melting and boiling points.

CBSE NCERT Solutions: InText Questions (Page 53)
Question 10: Define the following terms.
(i) Mineral (ii) Ore (iii) Gangue
Answer: (i) Mineral - The elements or compounds which occur naturally in the earth's crust are known as minerals.
(ii) Ore - At some places, minerals contain a very high percentage of a particular metal and the metal can be profitably extracted from it. These minerals are called ores.
(iii) Gangue - Ores mined from the earth are usually contaminated with large amounts of impurities such as soil, sand, etc, called gangue.

Question 11: Name two metals which are found in nature in the free state.
Answer: Gold, Platinum.

Question 12: What chemical process is used for obtaining a metal from its oxide?
Answer: The chemical process used for obtaining a metal from its oxide is reduction. The metal oxides are reduced by using a suitable reducing agent like carbon or by a more reactive metal to cause a displacement reaction. For example,




CBSE NCERT Solutions: InText Questions (Page 55)
Question 13: Metallic oxides of zinc, magnesium and copper were heated with the following metals.
Metal
Zinc
Magnesium
Copper
Zinc oxide



Magnesium oxide



Copper oxide




In which cases will you find displacement reactions taking place?
Answer:
Metal
Zinc
Magnesium
Copper
Zinc oxide
No
Yes
No
Magnesium oxide
No
No
No
Copper oxide
Yes
Yes
No

Question 14: Which metals do not corrode easily?
Answer: More reactive a metal, the chances of its corrosion is more. So, metals low in activity series, like gold, silver, etc. do not corrode easily.

Question 15: What are alloys?
Answer: An alloy is a homogenous mixture of two or more metals, or a metal and a non-metal.

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