Metals and Non-Metals - NCERT Answers of Class 10 NCERT Science Chapter 3 exercise questions

Metals and Non-Metals

Class 10 NCERT Solutions for Science Chapter 3 Textbook Exercise Questions

Question 1: Which of the following pairs will give displacement reactions?
(a) NaCl solution and copper metal.
(b) MgCl2 solution and aluminium metal.
(c) FeSO4 solution and silver metal.
(d) AgNO3 solution and copper metal.
Answer: (d)

Question 2: Which of the following methods is suitable for preventing an iron frying pan from rusting?
(a) Applying grease
(b) Applying paint
(c) Applying a coating of zinc
(d) All of the above.
Answer: (c)

Question 3: An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be
(a) Calcium
(b) Carbon
(c) Silicon
(d) Iron.
Answer: (a)

Question 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.
Answer: (c)

Question 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.
Answer: (a)
CBSE Guide NCERT Solution - image
By beating the samples with hammer we can check its malleability. If the sample is malleable then it is a metal otherwise non-metal. Similarly, we will make a circuit as shown in the figure and check the electrical conductivity of the sample. If with the sample (test material), the bulb glows on turning the switch on, the sample is likely to be a metal otherwise a non-metal.

(b) The above tests are generally useful in distinguishing between metals and non-metals. Since, these are based on only physical properties and no chemical reaction is involved in these tests. Only exception is graphite which is a good conductor of electricity although it is a non-metal.

Question 6: What are amphoteric oxides? Give two examples of amphoteric oxides.
Answer: The metal oxides are basic in nature. But some metal oxides show both acidic and basic behaviour and hence, react with both acids as well as bases to produce salts and water. These oxides are known as Amphoteric Oxides. For example, aluminium oxide reacts in the following manner with acids and bases:
Another example of amphoteric oxide is - Zinc oxide.

Question 7: Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
Answer: Metals that displace hydrogen: Magnesium, zinc. Metals that do not displace hydrogen: Copper, gold.

Question 8: In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?
Cbse Ncert Solution - image
In this process, the impure metal is made the anode and a thin strip of pure metal is made the cathode. A solution of the metal salt is used as an electrolyte. The apparatus is set up as shown in the above figure.

Question 9: Pratyush took Sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below.
(a) What will be the action of gas on
(i) dry litmus paper?
(ii) moist litmus paper?
(b) Write a balanced chemical equation for the reaction taking place.
Answer: (a) (i) No effect on dry litmus paper.
(ii) Turns blue litmus red in moist state. The gas is Sulphur dioxide, which will react with the H2O of moist blue litmus paper and form sulphurous acid (H2SO3). This acid turns blue litmus into red.
Question 10: State two ways to prevent the rusting of iron.
Answer: Rusting of iron can be prevented by making by it unable to come in contact with moisture and oxygen present in atmosphere. This can be done either by -
1. Galvanisation: A method in which a coating of zinc is made on the iron article.
2. By applying a coating of paint or grease or oil on the iron article.

Question 11: What types of oxides are formed when non-metals combine with oxygen?
Answer: Acidic oxides.

Question 12: Give reasons:
(a) Platinum, gold and silver are used to make jewellery.
(b) Sodium, potassium and lithium are stored under oil.
(c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
(a) Platinum, gold and silver are very less reactive and do not corrode. They also possess very brilliant lustre due to which jewelleries made with these metals look beautiful.
(b) Metals such as potassium, sodium and lithium react with air so vigorously that they catch fire if kept in the open. Hence, to protect them and to prevent accidental fires, they are kept immersed in kerosene oil.
(c) In spite of being a highly reactive metal, aluminium does not corrode easily. This is because aluminium reacts with oxygen present in air and forms a thin layer of aluminium oxide. This layer of aluminium oxide is very stable and thus, prevents further reaction of aluminium with oxygen. It is also a very good conductor of heat and light in weight. Because of the above reasons aluminium is used to make utensils for cooking.
(d) It is easier to obtain a metal from its oxide, as compared to its sulphides and carbonates. Therefore, prior to reduction, the metal sulphides and carbonates must be converted into metal oxides.  

Question 13: You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
Answer: It is because the basic oxides of copper like - copper oxide and copper carbonate formed on the copper vessels react with the acid present in the sour substances like lemon and tamarind and get dissolved and removed. Hence, lemon or tamarind and similar sour substances are used to clean copper vessels as they remove the corroded part of copper vessels and pure copper is exposed.

Question 14: Differentiate between metal and non-metal on the basis of their chemical properties.
Metals are positively charged ions (cation).
Non-metals are negatively charged ions (anion).
They react with the oxygen to form basic oxides.
They react with the oxygen to form acidic or neutral oxides.
Metallic oxides have Ionic bonds.
Non-Metallic oxides have Covalent bonds.
Metals also form amphoteric oxides after reacting with oxygen. (Some metal oxides are amphoteric oxides).
Non-metal oxides are not amphoteric oxides.
Metals react with water to form oxides and Hydroxides. Some metals react with cold water, some with hot water while others with steam.
Non-metals do not react with water.
They react with dilute acids to form salt and hydrogen gas. Exceptions: Cu, Ag, Au, Pt, Hg.
Non-metals do not react with dilute acids.
Depending on their reactivity, metals react with the salt solution of other metals. Example: CuSO4 + Zn ----> ZnSO4 + Cu
They react with the salt solution of non-metals.
Metals are generally reducing agents. Since, they can easily loose electrons.
Non-metals are generally oxidising agents. Since, they can easily gain electrons.

Question 15: A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?
Answer: The solution which the goldsmith used was aqua regia. It is a highly corrosive liquid and dissolves the gold in it.

Question 16: Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).
Answer: Copper doesn't react with water. But iron reacts with steam. So, if hot water tanks are made of steel which is an alloy of iron, then its iron content will react with steam formed from hot water. That is why, copper is used to make hot water tanks and steel is not.
 Class 10 NCERT Solutions CBSE Guide - Related Posts
  • CBSE Guide with solutions of CBSE Guess questions for Chapter 3, Metals and Non-metals (to be posted) 

Class 9, Peasants and Farmers - Solutions of CBSE Guide and Guess Questions for Chapter 6 NCERT History

Chapter 6, Peasants and Farmers

Class IX History CBSE Guide | CBSE Guess | CBSE History Questions Answers

Additional Short Answer type CBSE Guess Questions
Question 1: Who was Captain Swing?
Answer: It was a mythical name used in the threatening letters sent to the landowners to destroy their threshers themselves which deprived workmen of their livelihood.

Question 2: Why did the whole region of the Great Plains become a dust bowl?
Answer: The persistent drought during the 1930s coupled with the ever increasing greed of the zealous farmers who had recklessly uprooted all vegetation, facilitated the winds to blow with a furious speed and turn the whole region into a dust bowl.

Question 3: Which were the two major commercial crops grown in India in the 19th century during the colonial period?
Answer: Indigo and opium.

Question 4: What was the difference in making the enclosures in the 16th century and in the 18th century?
Answer: In the sixteenth century, the enclosures were made to promote sheep farming but in the eighteenth century, the enclosures were made to increase grain production.

Question 5: What were the advantages of the enclosures to the landlords?
(1) They were found necessary for long term investments on land.
(2) Enclosures proved useful for promoting sheep farming and increasing food production.
(3) Enclosures also enabled the richer landowners to expand the land under their control.

Question 6: In 1960s’ why did the farmers begin growing turnip and clove?
Answer: Because turnip and clove were good fodders for cattle. Moreover, cultivation of turnip and clove increased the nitrogen content of the soil which proved quite useful for the growth of other crops as well.

CBSE Guide for Class 9 Geography Lesson 6, Population | Solutions of CBSE long questions

NCERT Questions Bank | CBSE NCERT Solution | CBSE Guess | CBSE Guide NCERT Solution | CBSE Sample Questions

Class 9 Social Geography - Chapter 6, POPULATION

 Also study: Additional CBSE Questions Answers from this chapter already posted in our earlier posts (click the links given below)
Long Answer-Type CBSE Questions - image

Question 21. Write a short note on: Urbanisation in India.
What is the impact of fast - growing cities of India on the environment and available civic amenities?
Write a brief account on the impact of rapid urbanisation in India.
Why has the rapid growth of population in the metropolitan cities of India become a serious problem? Explain any five consequences of the same.
Answer: Many causes, such as relative stagnation of agriculture in rural areas, desire of the people to get jobs in towns and cities and attraction for facilities available in urban areas or cities, have led the rural people to migrate to urban areas.
Impact of Rapid Urbanisation in Fast Growing Cities of India:
But this migration of the people from rural to urban areas is very baneful or harmful. This has led to the rapid growth of population of cities, particularly of the metropolitan cities like Delhi, Mumbai, Calcutta, Chennai etc. Such a thing has led to various problems.
(1) Impact on Agriculture- In agriculture so many hands are required both at the sowing, reaping and the harvesting time. But when people would migrate to cities, the work in the fields is bound to suffer. In such a case, we once again can be forced to beg our food from other countries.
(2) Impact on Environment- When more and more people will migrate to cities, they would naturally expand beyond limits leading to various problems. The congestion in cities would have a very bad effect on environment. Too much smoke of numerous vehicles would lead to suffocation. Not only this, the need for more land for housing would have a very bad affect on greenery. Every green field around cities would be devoured within no time resulting in ecological imbalance. Even green parts within the city is on a constant decline giving place to slums and dirty congestions.
(3) Impact on Public Facilities- Every city has a limited scope for expansion. Its roads, sewage lines, water supply etc can cope with the needs of its residents to a certain limit. But the continuous migration of rural people to nearby cities even before creation of basic amenities is ultimately destructing the city infrastructure.
(4) Problem on Slums- The continuous flow of rural people to cities is giving rise to slums. These clusters of illegal structures with no amenities for water, sewage, toilets are a great blot on the fair name of the cities.
(5) Too Much Congestion- Cities are mostly congested but when more and more people flock them they become too much congested and prone to accidents. Over-crowding adds to pollution which is both dangerous and health-hazarding.
Question 22. Why is it important to study population?
What is the purpose of studying population?
Study of population is very important because -
(1) First of all by studying population, even after ten years, tell us the exact number of people in our country only by knowing the number of people living in our country. We can know where we are going and what steps we should take to avoid the coming catastrophe as a result of the unrestricted rise of population. No county can ever think of advancing forward with the addition of so many people in its population every year. So studying population is a must for every country.
(2) Secondly, by studying population, we can know the distribution of population in our country and where more emphasis is to be laid for the development and uplift of the area.
(3) Thirdly, by studying population, we can know the sex ratio in our country and take proper steps for the welfare of the weaker sections of the society including both woman and girl-child.
(4) Fourthly, only by studying population, we can know the age composition of the people and how much burden of the dependent population (children and old people) the working population has to bear.
(5) Fifthly, it is only by studying population, we can know as to how many people are engaged in primary, secondary and tertiary occupations and what steps we should take to bring about a change in occupational structure of our country.
(6) Sixthly, it is only by studying population that we can know the level of literacy in our country and think what steps we should take to remove illiteracy from our country.
(7) Seventhly, it is only by studying the data of our population, that we can know how many adolescents (people in the age group of 10 to 19) are there in our country and what special steps we can take to bring them up so that they may prove good citizens for the country.
(8) Lastly, it is by only studying population that we can chalk out our National Population Policy and think of measures both for containing the rise of our population and take desired methods for its welfare.

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Question 23. What could be the reason of uneven distribution of population in India?
What are the factors which influence the population distribution?
Answer: It is not only in India but uneven distribution of population or the varying population density is a worldwide phenomena. Population density in India varies from 904 persons per in West Bengal to only 13 persons per in Arunachal Pradesh. Following are the various reasons of uneven distribution of population in India:
(1) Geographical Factors- Favourable topography, availability of mineral and freshwater resources, favourable climate and soil fertility are some of the reasons affecting population distribution. For example, Indo-Gangetic Plains and Kerala in the South have high to very high density because of flat plains, fertile soils, abundant rains etc. States like Rajasthan, J&K, and Arunachal Pradesh etc. are sparsely populated because of unfavourable climate and topography.
(2) Social and Cultural Factors- Areas of better housing, education and health facilities are more populated. Places of religious and cultural significance also attract people. For example, Delhi, Varanasi etc.
(3) Economic Factors- Places having more industries, better transportation and communication facilities provide better employment opportunities. People from other areas migrate to these places because of the above reasons. For example- Mumbai, Bangalore, Delhi and other metropolitan cities and state like Punjab, Haryana, etc.
 Other study materials from Class IX, Chapter 6 Population
1. For NCERT answers of textbook exercise, click -
2. For important terms, Very Short and Short answer type CBSE questions, click -
3. For more click -
Class 9 Social Geography all Chapters’ solution and guide