CBSE Class 10 Chemistry Metals and Non Metals Worksheet Set E

CBSE Class 10 Chemistry Metals and Non Metals Worksheet Set E

METALS AND NON – METALS

Assertion and Reason Type MCQs :

Following questions consists of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
A. Both assertion and reason are true, and reason is the correct explanation of assertion.
B. Both assertion and reason are true, but reason is not the correct explanation of assertion.
C. Assertion is true but reason is false.
D. Assertion is false and reason is true.

Question. Assertion: Different metals have different reactivities with water and dilute acids.
Reason: Reactivity of a metal depends on its position in the reactivity series.

Answer: B

Question. Assertion: The property of beating a metal into sheets is called ductility.
Reason: Gold and silver are most malleable metals.

Answer: D

Question. Assertion (A): Hydrogen gas is not evolved when a metal reacts with nitric acid.
Reason (R): Nitric acid is a strong oxidising agent.

Answer: A

Question. Assertion: Iron is the most widely used metal. But it is never used in its pure state.
Reason: Pure iron is very soft and stretches easily when hot.

Answer: A

Question. Assertion: Electrovalency of Na is +1.
Reason: The number of electrons which an atom either loses or gains in the formation of an ionic bond is known as its valency.

Answer: B

Question. Assertion: The reaction of calcium with water is less violent in comparison to that of sodium.
Reason: The heat evolved is not sufficient for the hydrogen to catch fire.

Answer: B

Question. Assertion: Gold occurs in native state.
Reason: Gold is a reactive metal.

Answer: C

Question. Assertion: The oxides of sulphur and phosphorus are acidic in nature.
Reason: Metal oxides are basic in nature.

Answer: B

Question. Assertion(A): Zinc oxide is amphoteric in nature.
Reason (R): Zinc oxide reacts with both acids and bases.

Answer: A

CASE BASED MCQs

I. Metals as we know, are very useful in all fields, industries in particular. Non-metals are no less in any way. Oxygen present in air is essential for breathing as well as for combustion.
Non-metals form a large number of compounds which are extremely useful, e.g., ammonia, nitric acid, sulphuric acid, etc.
Non-metals are found to exist in three states of matter. Only solid non-metals are expected to be hard however, they have low density and are brittle. They usually have low melting and boiling points and are poor conductors of electricity.

Question. Which of the following non-metals is a liquid?
A. Carbon
B. Bromine
C. Iodine
D. Sulphur

Answer: B

Question. Hydrogen is used
A. for the synthesis of ammonia
B. for the synthesis of methyl alcohol
C. nitrogenous fertilizers
D. all of these

Answer: D

Question. Generally, non-metals are bad conductors of electricity but 'X' which is a form of carbon is a good conductor of electricity and is an exceptional non-metal. 'X 'is
A. diamond
B. graphite
C. coal
D . coke.

Answer: B

Question.____________ is a non-metal but is lustrous
A. Phosphorus
B. Sulphur
C. Bromine
D. Iodine

Answer: D

Question. Which of the following is known as 'King of chemicals'?
A. Urea
B. Ammonia X
C. Sulphuric acid
D. Nitric acid

Answer: C

II. When a silvery grey powder of a solid (A) is mixed with a powder of solid (B) no reaction occurs. But if the mixture is ignited and lighted using magnesium ribbon a reaction occurs with evolution of large amount of heat forming product (C) which settles down as liquid metal and the solid product(D) formed floats on the liquid (C). (C)in solid form reacts with moisture to form rust. The amount of heat generated during the reaction is so high that the reaction is used in welding of electric conductors, joints in railway tracks. Based on this information, answer the following questions.

Question. Amphoteric oxides are
A. metal oxides which do not react with acids but react with bases
B. metal oxides which reacts with both acids as well as bases
C. metal oxides which reacts with acids but do not react with bases
D metal oxides which shows no reaction with either acids or bases
4.Which of the following is amphoteric in nature?

Answer: B

Question. both aluminium oxide and zinc oxide
B. Only Zinc oxide
C. Only Aluminium oxide
D. Neither of them

Answer: A

Question. Identify A and C?
A. A- Al and C- Fe
B. A-Fe and C—Al
C. A-Mg and C -Al
D. A-Al and C -Cu

Answer: A

Question. Identify B and D which are oxides of
A. B- Fe , D- Al
B. B- Mg, D-Al
C. B- Al , D- Cu
D. B-Al , D -Fe

Answer: A

 

Short Answer type Questions

Question. Explain the various methods of preventing Rusting.
Answer : The various methods used for preventing the rusting of iron are given below:
(i) By applying paint : Materials like railings, iron gates, iron bridges, bodies of cars, buses and trucks, etc. are all painted to protect them from rusting. Painting the metal surface does not allow them to come in contact with the moist air and thus, prevents rusting.
(ii) Greasing and oiling: When some grease or oil is applied on the surface of an iron object, then moisture and air cannot come in contact with it and hence, rusting is prevented.
(iii) Galvanization: It is a method of protecting iron from rusting by coating them with a thin layer of zinc. The iron coated with zinc is called galvanized iron.
(iv) Electroplating: It is another technique used to prevent articles from rusting. In this process, metals like tin, nickel and chromium which do not corrode are electroplated on iron.

Question. Define the terms:
(i) Mineral (ii) ore, and (iii) gangue.
Answer : (i) Mineral: It is a naturally occurring substance from which metal may or may not be extracted profitably or economically, e.g. A1 cannot be extracted profitably from mica.
(ii) Ore: It is a rocky material which contains sufficient quantities of minerals so that metal can be extracted profitably, e.g., zinc blende is an ore of zinc from which zinc can be extracted profitably.
(iii) Gangue: It is a rocky material which is present along with the mineral in the ore, e.g.,
FeO is gangue in extraction of copper.

Question. How does metal displace Hydrogen from acid. Give Chemical equation.
Answer : Hydrogen is displaced by the metals from acids that are placed above hydrogen in the reactivity series of the metals.
This is because these metals are more reactive than hydrogen.
Ex: Reaction of calcium with hydrochloric acid.
Ca+2HCl→CaCl₂+H₂
Here, Hydrogen is displaced by Calcium from Hydrochloric acid.

Question. Why do some metal surfaces acquire a dull appearance when they are exposed to moist air? Write colour acquired by the surfaces of copper and silver in such a situation and also write the chemical names of the substances due to which it happens.
Answer : When a metal has been kept exposed to air for a long time, then it gets a dull appearance. The metals lose their shine or brightness due to the formation of a thin layer of oxide, carbonate or sulphide on their surface and thus, the metal surface gets corroded.
The surface of copper gets coated with a green layer in moist air due to the formation of basic copper carbonate, silver articles acquire a blackish tinge due to the formation of silver sulphide.

Question. Why some metal surfaces acquire a dull appearance when they are exposed to moist air? Write colour acquired by the surfaces of copper and silver in such situation and also write the chemical names of the substances due to which it happens.
Answer : When a metal has been kept exposed to air for a long time, then it gets a dull appearance. The metals lose their shine or brightness due to the formation of a thin layer of oxide, carbonate or sulphide on their surface and thus, the metal surface gets corroded.
The surface of copper gets coated with a green layer in moist air due to the formation of basic copper carbonate, silver articles acquire a blackish tinge due to the formation of silver sulphide.

Question. Suggest a method of reduction for the following metals during their metallurgical processes:
(i) Metal ‘A’ which is one of the last, second or third positions in the reactivity.
(ii) Metal ‘B’ which gives a vigorous reaction even with water and air.
(iii) Metal ‘C’ which is kept in the middle of activity series.
Answer : (i) ‘A’ can be obtained by chemical reduction using carbon or carbon monoxide as a reducing agent.
(ii) ‘B’ can be obtained by electrolytic reduction.
(iii) ‘C’ can be reduced by reducing agents like ‘Al’.

Question. Carbon cannot reduce the oxides of sodium, magnesium and aluminium to their
respective metals. Why? Where are these metals placed in the reactivity series? How are these metals obtained from their ores? Take an example to explain the process of extraction along with chemical equations.
Answer : Sodium, magnesium and aluminium have higher affinity towards oxygen than that of carbon because these are highly reactive metals. Hence, carbon cannot reduce the oxides of sodium, magnesium, and aluminium to their respective metals.
These metals are placed at the top of the reactivity series. The highly reactive metals like Na, Mg, Al, etc. are extracted by electrolytic reduction of their molten chlorides or oxides. Electrolytic reduction is brought about by-passing electric current through the molten state. Metal gets deposited at the cathode.
NaCl ⇌ Na⁺ + Cl^–
At cathode: Na⁺ + e^– → Na
At anode: 2Cl^– → Cl₂ + 2e^–

Question. Aluminium is a reactive metal but is still used for packing food articles. Give reason.
Answer : Aluminium is a strong and cheap metal. It is also a good conductor of heat. But it is highly reactive. When it is exposed to moist air, its surface is covered with a thin impervious layer of aluminium oxide (Al₂O₃). This layer does not allow moist air to come in contact with the fresh metal and hence, protects the metal underneath from further damage or corrosion. Thus, after the formation of this protective layer of Al₂O₃, aluminium becomes resistant to corrosion. It is because of this reason that although aluminium is a highly reactive metal, it is still used in food packaging.

Question. (a) Define corrosion.
(b) What is corrosion of iron called?
(c) How will you recognize the corrosion of silver?
(d) Why is corrosion of iron a serious problem?
(e) How can we prevent corrosion of iron?
Answer : (a) The process of slowly eating up of metals due to their conversion into oxides, carbonates, sulphides, etc., by the action of atmospheric gases and moisture is called corrosion.
(b) The corrosion of iron is called rusting.
(c) Silver articles become black after some time when exposed to air. This is due to formation of a coating of black silver sulphide (Ag₂S) on its surface by the action of H2S gas present in the air.
(d) Corrosion of iron is a serious problem. Every year a large amount of money is spent to replace damaged iron articles. Corrosion causes damage to car bodies, bridges and iron railings, ships and to all objects made of metals especially those of iron.
(e) Corrosion of iron is prevented by coating it with a layer of oil. The reason being that the layer of oil does not allow air and water to react with the surface of iron. Corrosion of iron can also be prevented by painting, greasing, galvanizing, anodizing, electroplating or making alloys.

Question. What are alloys? How are they made? Name the constituents and uses of brass, bronze and solder.
Answer : Alloys are homogeneous mixtures of two or more metals. One of them can be nonmetal also. They are made by melting a large amount first and then adding the other metal.
Brass contains copper and zinc. It is used for making decorative articles. Bronze contains copper and tin. It is used for making statues and medals. Solder contains lead and tin. It is used for soldering purposes.

ORAL QUESTIONS

1. Name the metal which is a liquid.

2. Name the non – metal which shows lustre.

3. Name the lightest metal.

4. Name the metal with highest density.

5. Name the property of the metals by virtue of which these can be beaten into sheets

6. Name the property of the metals by virtue of which these can be drawn into wires.

7. Name the material which is kept in water.

8. Name the metal used for galvanisation of iron.

9. Mercury is liquid and a good conductor of heat. How is this property utilized?

QUIZ – WHO AM I

1. I am a property of metals which appears at lower temperatures.

2. I am noble conductor of heat and electricity.

3. Though I get corroded in atmosphere but still find wide applications for making kitchen utensils.

4. I am a metal but very soft and cannot be kept in the open.

5. I am called a series and play a significant role when a metal reacts with solutions of other metal salts.

6. Scientists / Industrialists use me to extract metals profitably and economically.

7. I am a process to refine metals of high reactivity.

8. I am a process associated with wasting away of metals by the action of atmospheric gases and moisture

9. I am homogenous and not a compound though my formation least to altering the properties of metals involved.

10. We belong to the same category of elements but still combine to form molecules / compounds.

PUZZLES

1. => Across

1. Property of metals to give long wires. (9) 3. Solid solution of metal (6)

↓ Down

2. Three dimensional networks of ionic compounds (7).

3. Process of heating concentrated ores in the absence of air (11)

2. =>  Across

1. Property of metals to give sheets. (12)

3. Refined naturally occurring inorganic solid from which metal is extracted economically(3)

↓ Down

2. Property of metals to allow passage of heat or electricity (12).

3. A series determined by electropositive character of metals (10)

SEMINAR

1. Significance of alloys in modern life.

2. Harmful effects of corrosion in industry and method by which it can be prevented.

PROJECT

Students may collect different small articles which are made of different alloys (such as stainless steel, brass, bronze, solder, and duralumin). They may also use pictures of articles made of different alloys and paste in the project file.