NCERT Solutions for Class 10 Science Chapter 3

NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals intext questions given on Page 40 or Page 46 or Page 49 or Page 53 or Page 55 or Exercises in English Medium updated for new session 2020-21.

The Hindi Medium version of solutions including पेज 45 के उत्तर or पेज 51 के उत्तर or पेज 54 के उत्तर or पेज 59 के उत्तर or पेज 61 के उत्तर or अभ्यास के प्रश्न उत्तर are also given to study online or download in PDF form free. NCERT Books and Offline Solutions Apps 2020-21 based on latest CBSE Syllabus 2020-21 are also available to download.

NCERT Solutions for Class 10 Science Chapter 3

Class:10
Subject:Science – विज्ञान
Chapter 3:Metals and Non-Metals

10th Science Chapter 3 Answers in English & Hindi Medium

NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals all intext question answers and chapter end exercises are given below to free download or use online. All NCERT Solutions 2020-21 are updated for new academic session based on latest CBSE Syllabus 2020-2021.

Why are aluminium and copper metals used for making cooking vessels?

Aluminium and copper metals are good conductor of heat. When exposed to air, these develop a layer of oxide. This makes it resistant to further corrosion.

Why is sodium kept immersed in kerosene oil?

Sodium is very reactive. If kept exposed to air, it catches fire.

Distinguish between calcinations and roasting.

Calcination:
(i) The ore is heated is absence of air.
(ii) It is used for carbonate ores.
Roasting:
(i) The ore is heated in the presence of air.
(ii) It is used for sulphide ores.

Ionic compounds have high melting point. Why? Give reason in support your answer.

In iconic compounds, ions are joined together due to powerful electrostatic forces, therefore, considerable energy is required to separate these ions and break the lattice. Thus ionic compounds have high melting points.

Generally, Ionic compounds are hard crystalline solids. Why?

There are solids due to strong force of attraction between oppositely charged ions resulting in the formation of hard crystalline lattice.

What are alloys?

An alloy is a homogeneous mixture of two or more metals, or a metals and a non-metal. It is prepared by first melting the main metal, and then dissolving the required amount of other metals or non-metals. This mixture is then cooled to form an alloy of a given composition.

What is meant by metallurgy?

Metallurgy involves various processes starting with the treatment of ore to getting metals in the pure form.

Questions for Practice

Question 1:
Compare the properties of a typical metal and non-metal on the basis of the following:
(i) nature of oxide formed by them
(ii) conductivity.
Answer :
(i) Metals from basic oxide, e.g., sodium gives a basic oxide, Na2O. Non-metals from acidic oxide, e.g., sulphur gives an acidic oxide, SO2.
(ii) Metals have good conductivity, e.g., copper is a good conductor. Non-metals do not conduct heat or electricity, e.g., sulphur.

Question 2:
How is an ore different from a mineral?
OR
“all ores are minerals but all minerals are not ores”. Justify the statement with examples.
Answer 2:
The metals found in nature in combined state are called minerals. If some minerals contain a very high percentage of a particular metal and the metals can be profitably and economically extracted, then it is called an ore.

Questions from Board Papers

Question 1:
Atmospheric air always contains moisture. Then, how can you protect iron articles from the affect of atmosphere?
Answer 1:
Iron articles can be protected from the effect of atmosphere by painting, oiling and greasing. This gives temporary protection to iron articles. For long time protection, galvanising or chrome plating are quite useful.

Question 2:
Explain, why some metals are more reactive and others less reactive and others less reactive?
OR
What determines the reactivity of metals?
Answer 2:
When metals react, they lose electrons to form positive ions. Such metals which can lose electrons easily to form positive ions when reacted with other substances, are reactive metals. On the other hand, if a metal loses electrons less rapidly to form positive ions, it will reacts slowly with other substances. Such a metal will be less reactive. For example, sodium atom is a very reactive metals because it readily loses one electron, forms a positive ion which then combines with other substances. On the other hand, lead atom loses electrons with difficulty to form positive ions, so lead metal is less reactive.

Important Questions on 10th Science Chapter 3

Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
Metals that are more reactive than hydrogen displace it from dilute acids.
For example: sodium and potassium.

Metals that are less reactive than hydrogen do not displace it.
For example: copper and silver.

What are the two important ways to prevent the rusting of iron?
Oiling, greasing, or painting: By applying oil, grease, or paint, the surface becomes water proof and the moisture and oxygen present in the air cannot come into direct contact with iron. Hence, rusting is prevented.

Galvanisation: An iron article is coated with a layer of zinc metal, which prevents the iron to come in contact with oxygen and moisture. Hence, rusting is prevented.

Platinum, gold and silver are used to make jewellery. Why?
Platinum, gold, and silver are used to make jewellery because they are very lustrous. Also, they are very less reactive and do not corrode easily.
Why are Sodium, potassium and lithium stored under oil?
Sodium, potassium, and lithium are very reactive metals and react very vigorously with air as well as water. Therefore, they are kept immersed in kerosene oil in order to prevent their contact with air and moisture.
Aluminium is a highly reactive metal, yet it is used to make utensils for cooking. Why?
Though aluminium is a highly reactive metal, it is resistant to corrosion. This is because aluminium reacts with oxygen present in air to form a thin layer of aluminium oxide. This oxide layer is very stable and prevents further reaction of aluminium with oxygen. Also, it is light in weight and a good conductor of heat. Hence, it is used to make cooking utensils.
Carbonate and Sulphide ores are usually converted into oxides during the process of extraction. Why?
Carbonate and sulphide ores are usually converted into oxides during the process of extraction because metals can be easily extracted from their oxides rather than from their carbonates and sulphides.

NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals page 40
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals page 46
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NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals page 49
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals page 53
NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals page 55
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