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NCERT Class 10 Science Textbook Chapter 3 With Answer PDF Free Download
Chapter 3: Metals And Non Metals
3.1 Physical Properties
The easiest way to start grouping substances is by comparing their physical properties. Let us study this with the help of the following activities.
For Activities 3.1 to 3.6, collect the samples of the following metals – iron, copper, aluminum, magnesium, sodium, lead, zinc, and any other metal that is easily available.
You will find that metals are generally hard. The hardness varies from metal to metal. You will find that some metals can be beaten into thin sheets.
This property is called malleability. Did you know that gold and silver are the most malleable metals?
The ability of metals to be drawn into thin wires is called ductility. Gold is the most ductile metal.
You will be surprised to know that a wire of about 2 km in length can be drawn from one gram of gold. It is because of their malleability and ductility that metals can be given different shapes according to our needs.
Can you name some metals that are used for making cooking vessels? Do you know why these metals are used for making vessels? Let us do the following Activity to find out the answer.
The above activity shows that metals are good conductors of heat and have high melting points. The best conductors of heat are silver and copper. Lead and mercury are comparatively poor conductors of heat.
You must have seen that the wires that carry current in your homes have a coating of polyvinylchloride (PVC) or a rubber-like material. Why are electric wires coated with such substances?
What happens when metals strike a hard surface? Do they produce a sound? The metals that produce a sound on striking a hard surface are said to be sonorous. Can you now say why school bells are made of metals?
In the previous Class, you have learned that there are very few non-metals as compared to metals. Some examples of non-metals are carbon, sulfur, iodine, oxygen, hydrogen, etc.
The non-metals are either solids or gases except bromine which is a liquid. Do non-metals also have physical properties similar to that of metals?
On the bases of the observations recorded in Table 3.1, discuss the general physical properties of metals and non-metals in the class. You must have concluded that we cannot group elements according to their physical properties alone, as there are many exceptions.
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NCERT Solutions Class 10 Science Chapter 3 Metals And Non-Metals
2. Which metals do not corrode easily?
Solution: Gold and platinum are the metals that do not corrode easily
3. What are alloys?
Solution: An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal.
Exercise questions Page number 56-57
1. Which of the following pairs will give displacement reactions?
(a) NaCl solution and copper metal
(b) MgCl2 solution and aluminum metal
(c) FeSO4 solution and silver metal
(d) AgNO3 solution and copper metal
Solution: Option d i.e AgNO3 solution and copper is the correct answer. Copper displaces the silver cations (reducing them to the elemental metal), and in the process copper itself is oxidized to Copper II cations (Cu2+) and goes into solution. So silver metal precipitates out and a copper II nitrate solution will be remaining.
Cu(s) + 2AgNO3 (aq) → Cu(NO3)2 (aq) + 2Ag (s)
2. Which of the following methods is suitable for preventing an iron frying pan from rusting?
- Applying grease
- Applying paint
- Applying a coating of zinc
- All of the above
Solution: Answer is (c) Applying a coat of Zinc
Though applying grease and applying paint prevents iron from rusting but we cannot apply these methods to a frying pan hence applying a coat of Zinc is the most appropriate method to prevent an iron pan from rusting.
3. An element reacts with oxygen to give a compound a high melting point. This compound is also soluble in water. The element is likely to be
Solution: Correct answer is option (a) i.e Calcium.
Calcium reacts with oxygen to give calcium oxide. Calcium oxide is soluble in water to give Calcium Hydroxide.
Carbon forms carbon-oxide with oxygen which is gas hence option B is wrong
Silicon reacts with oxygen and forms silicon dioxide. This is insoluble in water. So option C is not correct.
Iron reacts with oxygen and forms Iron dioxide. This is insoluble in water. So option D is not correct.
4. Food cans are coated with tin and not with zinc because
(a) Zinc is costlier than tin.
(b) Zinc has a higher melting point than tin.
(c) Zinc is more reactive than tin.
(d) Zinc is less reactive than tin.
Solution: The answer is c. Food cans are coated with tin and not with zinc because zinc is more reactive that is electropositive than tin.
5. You are given a hammer, a battery, a bulb, wires, and a switch.
(a) How could you use them to distinguish between samples of metals and non-metals?
(b) Assess the usefulness of these tests in distinguishing between metals and non-metals.
- Metals are malleable and can be easily drowned into sheets by hitting with a hammer. On the other hand, if we beat non-metals they break down and they cannot be drawn into sheets as they are non-malleable. Metals of good conductors of electricity hence they make bulb when you connect metals with a battery, wire, and bulb. Similarly, If non-metals are bad conductors of electricity chance they fail to light up the bulb on connecting with wire and battery.
- These experiments can be helpful to demonstrate the malleability and electric conductivity of the metals and non-metals
6. What are amphoteric oxides? Give two examples of amphoteric oxides
Solution: Oxides that react with both acids and bases to form salt and water are known as amphoteric oxides. Examples: PbO and Al2O3.
Amphoteric oxides are the one that reacts with both acids and bases to form salt and water. Examples: Lead oxide – PbO and Aluminium oxide – Al2O3.
7. Name two metals that will displace hydrogen from dilute acids, and two metals which will not.
Solution: Zinc (Zn) and Magnesium (Mg) are the two metals that will displace Hydrogen from dilute acids as they are very reactive metals. Gold (Au) and Silver (Ag) are the metals that will not replace Hydrogen from dilute acids as these metals are less reactive.
8. In the electrolytic refining of a metal M, what would you take as the anode, the cathode, and the electrolyte?
Solution: In the process of electrolytic refining of metal called ‘M’, An impure and thick block of metal M. is considered as anode, Thin strip or wire of pure metal M is taken as the cathode. A suitable salt solution of metal M is considered as the electrolyte.
Metals And Non-Metals NCERT Textbook With Solutions PDF Free Download