Class 10 Science Chapter 3 Important Questions

Class 10 Science Chapter 3 Important Questions of Metal and Non-Metals prepared for the revision for board exams 2020-2021 based on latest NCERT Books 2020-21 following the latest CBSE Curriculum 2020-2021.

Sets of Important Questions contains all the questions from NCERT Books of class 10 Science Chapter 2 and it provides the complete revision for Metals and Non-Metals.

Class 10 Science Chapter 3 Important Questions 2020-21

Class:10
Subject:Science
Contents:Important Questions

Class 10 Science Chapter 3 Important Questions for exams

Class 10 Science Chapter 3 Important Questions are given below for the preparation of CBSE, UP Board, Gujrat Board, Uttarakhand, MP Board and all other boards who are following the latest CBSE NCERT Books as course books. All the important terms, definitions, experiment based questions, conceptual questions and intext questions of NCERT Textbook are included in the sets of Important Questions.

10th Science Chapter 3 Important Questions Set – 1

How are the metals different in reactivity with O2?

(i) Sodium and Potassium react so vigorously if it kept in open it catches fire that’s why it is kept immersed in Kerosene.
(ii) Magnesium, Aluminium, Zinc, Lead are the metals which covered with a thin layer of Oxide on the surface of it which prevent it from the further oxidation.
(iii) Iron does not burn on heating but iron fillings burn on heating.
(iv) Copper does not burn but it is coated with a black copper oxide.
(v) Silver and Gold are the metals which does not react with oxygen because it is very low reactive metal.

What happen when metal react in air?

Metals combine with oxygen to forms metal oxide.
Metal + O2 → Metal oxide
For example:
Na + O2 → NaO2
2Cu + O2 → 2CuO
K + O2 → K2O
4Al + 3O → 2Al2O3

What do you understand by the Amphoteric oxide?

Amphoteric oxide is a type of metal oxide which react with both acids as well as base.

For example:
Al2O3 + 2NaOH → 2NaAlO2 + H2O
Al2O3 + 6HCl → 2AlCl3 + H2O

What are the reaction of metal according to the reactivity series?

(i) K, Na, Ca react with cold H2O.

(ii) Al, Fe, Zn react with steam.

(iii) Fe, Sn react with hot H2O.

(iv) Pb, Cu, Ag, Au are the metals which does not react with H2O.

(v) Ca and Mg float as bubble H2 stick to their surface.
Examples:
3Fe + 4H2O → Fe3O4 + 4H2
2Na + 2H2O → 2NaOH + H2 + Heat
Ca + 2H2O → Ca(OH)2 + H2

Properties of Metals

(i) Metals are lustre and having shinning surface.
(ii) Metals are generally hard except sodium, Lithium and potassium which are soft and it easily cut with a knife.
(iii) Metals always exist in solid state except mercury.
(iv) Metals have the property of malleability it can beaten for the preparation of thin sheet. Gold and silver are the most malleable metal.
(v) Metals have the property of ductility so metals can be preparing into thin wire.
(vi) Metals are good conductor of heat and electricity. For example, silver and copper are good conductor of heat but lead and mercury are poor conductor of electricity.
(vii) Metals have high melting point except sodium and potassium they are very soft metal.
(viii) Metals are sonorous that’s why metal produce a sound when strike with a hard surface.
(ix) Metals form oxide which is basic in nature.

10th Science Chapter 3 Important Questions Set – 2

What happen when metal react with acids?

When metal react with acid salt and water will produces.
For example:
Fe + 2HCL → FeCl2 + H2
Mg + 2HCL → MgCl2 + H2
Zn + 2HCL → ZnCl2 + H2

What happen when a metal reacts with other metal salt?

Metal A + Salt of metal B → Salt solution A + metal B
If a metal is more reactive than so it displaces the less reactive metal.
For example:
Na + HCl → NaCl + H2
Ca + H2SO4 → CaSO4 + H2
These two reaction are exothermic.

What are ionic compound?

Ionic compound are those compound which contain both metal and non-metal ions in this compound strong compound strong force of attraction take place between ions.

What are the properties of ionic compound?

Properties of ionic compound are:
(i) Ionic compound conduct electricity in aqueous solution but it cannot cannot conduct electricity in dry or solid form.
(ii) Physical Nature: It is solid in nature and also very hard because strong force of attraction between the positive and negative ions.
(iii) Melting and boiling: It has high melting point and boiling point.
(iv) It is soluble in water but it does not dissolve in organic solvent like: Petrol, Oil etc.

What do you understand by the Aqua Regia?

It is the only reactant that is capable of dissolving metals like gold and platinum. It is obtained by mixing concentrated hydrochloric acid and concentrated nitric acid in the ratio of 3:1. Aqua Regia is also known as Royal water.

Properties of Non-Metals

(i) Non-metals are not lustre they do not have shinning surface except iodine.
(ii) Non-metals are generally soft except diamond it is a form of carbon which is the natural hardest natural substance.
(iii) Non-metals are existing in solid or gaseous state except bromine.
(iv) Non-metals are non-malleable in nature.
(v) Non-metals are non-ductile.
(vi) Non-metals are poor conductor or heat and electricity except graphite it is a good conductor of heat and electricity.
(vii) Non-metals have low density have having very low melting point.
(viii) Non-metals are not sonorous they do not produce any sound when strike with other object.
(ix) Non-metals forms oxide which is basic in nature.

10th Science Chapter 3 Important Questions Set – 3

What are properties used when a metal reacts with Non-metal?

(i) Reactivity of the element is the tendency to attain a completely filled balanced shell.
(ii) Atom of the metal lose electron from their balance shell to form cation. Atom of the non-metal gain electron in the valence shell to form anion.

What are the steps that take place in the extraction of metals?

On the basic of reactivity series we can group the metals into three group:
(i) Metals of high reactivity: For example, potassium, sodium, calcium, magnesium and Aluminium.
(ii) Metals of medium reactivity: For example, zinc, iron, lead etc.

How is the enrichment of ores done?

Ores are generally contaminated with impurities, such as soil, sand, etc., called gangue. These impurities must be removed from the ores before proceeding to extraction. The method used for removing gangue depend upon the physical and chemical properties of the gangue and the ores.

How do you extract teh metals with low reactivity?

Low reactive are very unreactive. For example, cinnabar(HgS) is an ore of mercury. When heated it is first converted to mercury oxide which on further heating changes to metallic mercury.
2HgS + 3O2 → 2HgO + 2SO2
2HgO → 2Hg + O2
Similarly copper which occurs in nature as Cu2S can be obtained by just heating in air.
2CuS + 3O2 → 2CuS + 2SO2
2Cu2O + Co2S → 6Cu + SO2

Occurrence of Metals

Element of compound which occur naturally in the earth crust known as minerals. Minerals from which metals can be extracted profitably are called ores. Seawater also contain some soluble salts such as Sodium chloride, magnesium chloride, etc.

10th Science Chapter 3 Important Questions Set – 4

What do you understand by the Reduction reaction?

It is a type of process in which a metal oxide are reduced to corresponding metal by using reducing agent like carbon.
ZnO + C → Zn + CO

How do you extract the top element from the activity series?

The metals at the higher end of the activity series are very reactive. Their oxide cannot be reduced with carbon because the metal has greater affinity for oxygen than carbon. Such metals are obtained by electrolytic reduction. Sodium, magnesium and calcium are obtained by the electrolytic reduction of their molten chlorides. The metals are obtained at the cathode while chlorine is liberated at the anode.
The reaction may be represent as
Na+ + e- → Na At cathode
2Cl- → Cl2 + 2e- At anode

What do you understand by the Thermit Process?

The reaction of iron oxide Fe2O3 with Aluminium is an exothermic process. Iron is obtained in molten state which is used to join railway tracks or cracked machine parts. This reaction is known as thermit reaction and the process is known as thermit process.
Example: Fe2O3 + 2Al → 2Fe + Al2O3 + Heat

What is meant by corrosion? State with example.

The surface of some metal get corrode when they exposed in the contact of moist air for a very long period so this is called corrosion.
For examples:
(i) Silver articles turn black when exposed to air. This is because it reacts with Hydrogen Sulphide in air to form Silver Sulphide which is black.
(ii) Similarly copper articles turn green due to reaction with atmospheric carbon dioxide forming green copper carbonate.
(iii) Iron gets rusted when exposed to moist air from brown oxide of iron.

The Process of Electrolytic Refining

In the process of electrolytic refining we use metal such as copper nickel, etc and remove all the impurities and made a new metal. We take two test tube one is thin and other is big and take a dissolve solution of CuSO4 and in a big tube we put impure Cu and provide electricity in it so through the big test tube leave two electrons and it enters in the thin test tube and combine with two other ions that is already present their Cu+2 +2x in the process all the anode mud store at the downward. The impure metal is made the anode and the anode and a thin strip of pure metal is middle at the cathode. A solution of metal salt is used as electrolyte. The apparatus on passing current through the electrolyte the pure metal from the anode dissolve into the electrolyte. An equivalent amount of pure metal from the electrolyte is deposit on the cathode. The soluble impurities go into the solution.

10th Science Chapter 3 Important Questions Set – 5

What are the methods used for the prevention of Corrosion?

Rusting of iron metal can be preventing by the following method:
(i) by painting the surface.
(ii) by oiling or greasing the surface.
(iii) galvanizing, chrome plating, anodising or making alloy.

Explain the method of galvanization?

It is a method of protecting steel and iron from rusting. The article is coated with a thin layer of zinc. Galvanized article is protected against rusting even if coating is broken.

What is meant by the 22-carat gold?

Pure gold which is 24-carat gold is very soft and is not suitable for making ornaments. It is alloyed with either copper or silver to make it hard. Generally, in India 22carat gold is good for making jewellery, it means 22 part of gold is alloyed with 2 part of copper or silver.

What do you understand by the acidic or basic oxide?

Basic oxide: Those oxides which react with acids or acidic oxide to form salt and water are called basic oxide. Metal react with oxygen to form metallic oxide which are generally basic in nature example Na2O (sodium oxide) CaO (calcium oxide) K2O (potassium oxide) MgO (magnesium oxide) are basic oxide.
MgO + 2HCl → MgCl2 + H2O
Acidic oxide: Those oxides which react which react with bases or basic oxide to form salt and water are called acidic oxides. Non-metals react with oxygen to form non-metallic oxide which are generally acidic in nature example CO2 (carbon dioxide), SO2(Sulphur dioxide), K2O (potassium oxide), SO3 (Sulphur trioxide), P2O5 (phosphorus pentoxide) SiO2 (silicon dioxide) are acidic oxides.
CO2 + 2NaOH → Na2CO3 + H2O

Alloying

It is method of improving the properties of a metal. If iron is mixed with a small amount of carbon (about 0.05%) it became hard and strong. When iron is mixed with nickel and chromium, we obtain stainless steel which is hard and does not rust. An alloy is a mixture of two or more metals or a metal and a non-metal. It is prepared by first melting the primary metal and then dissolving the other element in a definite proportion. It is then cooled at room temperature.

10th Science Chapter 3 Important Questions Set – 6

Explain the process of Hydraulic Washing?

It is process in which crushed (powdered) ore is washed with stream of water. The light gangue particle is washed away in a stream of water whereas heavy mineral particle is settle down at the bottom. It is based on difference in density of an ore and impurities.

What do you understand by the froth floatation process?

This process is used to concentrate some ores especially Sulphide ores. In this process the finely powdered ores is mixed with water and a suitable oil like pine oil, in a large tank. It is based on the principal that the mineral particle is more wetted by oil, whereas the gangue particle is more wetted by water. Compressed air is bubbled through the mixture. As a result of agitation oil froth is formed which contain mineral which float on the top of water and can be separated easily. Impurities are left behind at the bottom.

What is meant by the magnetic separation?

It is a process in which a magnetic ore is separated from non-magnetic impurities with the help of electromagnet. The ore is crushed and electromagnet are brought near it which attract the mineral particle leaving behind the gangue particle. Magnetite (iron ore Fe3O4) pyrolusite (magnesium ore MnO2), chromite (chromium ore Cr2O3) are enriched by magnetic separation.

What are the properties of Alloys?

Alloy of a metal with mercury is known as amalgam. It has been observed that melting point and electrical conductivity of an alloy are lower than those of the constituent metals. For example, brass which is an alloy of copper and zinc and bronze which is an alloy of copper and tin are not as good conductor of electricity as copper. Solder which is an alloy of lead and tin has a low melting point and it is used for welding electrical wires.

Roasting and Calcination

Roasting: The Sulphide ore is converted into oxide are by heating strongly in the presence of excess air. This process is known as roasting.
For example:
2ZnS + 3O2 → 2ZnO + 2SO2

Calcination: The carbonate ore is changed into oxide by heating strongly in limited supply of air. This is known as calcination.
For example:
ZnCo3 → ZnO + CO2

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