CBSE Class 10 Chemistry Metals and Non Metals Worksheet Set C

Question. Why does a metal not release H₂ gas on reacting with dilute nitric acid? 
Answer : As nitric acid acts as a strong oxidising agent and oxidises the released H₂ gas to H₂O and itself is reduced to either of these gases—N2O, NO2 or NO.

Question. State two ways to prevent the rusting of iron.
Answer : Rusting of iron can be prevented:
(i) by galvanizing the iron articles with zinc.
(ii) by painting and applying grease on the iron articles.

Question. What type of oxides are formed when non-metals combine with oxygen?
Answer : Non-metals form acidic oxides with oxygen. These oxides turn blue litmus red.

Question. Why is copper used to make hot water tanks whereas steel is not? 
Answer : Copper is a better conductor of heat as compared to steel. Therefore, hot water tanks are made of copper.

Question. (a) Draw a flow diagram to show extraction of metals of medium reactivity from their sulphide ore.  
(b) Differentiate between roasting and calcination. 
Answer : (a) Flow diagram to show extraction of metals of medium reactivity from their sulphide ore:

Short Answer Questions

Question. How are covalent bonds formed ?
Answer : Covalent bonds are formed by the sharing of electrons between atoms. By sharing their outermost valence electrons, atoms can fill up their outer electron shell and gain stability.

Question. Silver articles become black when kept in open for some time, whereas copper vessels lose their shiny brown surfaces and gain a green coat when kept in open. Name the substances present in air with which these metals react and write the name of the products formed.
Answer : Silver articles become black when kept in open for some time, whereas copper vessel lose their shiny brown surfaces and gain a green coat when kept in open because silver articles reacts with sulphide compounds such as hydrogen sulphide present in the air to form silver sulphide (Ag₂S) whereas copper reacts slowly with CO₂ and water present in the air to form green coating of mixture of copper carbonate and copper hydroxide.

Question. Name one metal which has a low melting point.
Answer : Cesium.

Question. What name is given to those metal oxides which show basic as well as acidic behaviour ?
Answer : Amphoteric oxides.

Question. Name two metals which form amphoteric oxides.
Answer : Aluminium and zinc.

Question. Give an example of a metal which : 
(a) is a liquid at room temperature.
(b) can be easily cut with a knife.
(c) is the best conductor of heat.
(d) is a poor conductor of heat.
Answer : (a) Metal that exists in liquid state at room temperature → Mercury
(b) Metal that can be easily cut with a knife → Sodium, Potassium
(c) Metal that is the best conductor of heat → Silver, Gold
(d) Metals that are poor conductors of heat → Mercury and lead

Question. Explain the following :
(a) Sodium chloride is an ionic compound which does not conduct electricity in solid state where as it does conduct electricity in molten state as well as in aqueous solution.
(b) Reactivity of aluminium decrease if it is dipped in nitric acid.
(c) Metals like calcium and magnesium are never found in their free state in nature. 
Answer :
(a) Sodium chloride is an ionic compound but it conducts electricity only in molten and aqueous state because in molten and aqueous form the compound liberate to give ions. These ions move freely and hence conduct electricity.
(b) Reactivity of aluminium decreases if it is dipped in nitric acid because it is a strong oxidising reagent.The layer of aluminium oxide (Al₂O₃) prevents further reaction of aluminium due to which its reactivity decreases.
(c) Metals like calcium and magnesium are never found in their free states in nature they occur in the form of ores because these metals are present on the top of the reactivity series. They are highly reactive that they react with gases and surrounding elements, form compounds and thus are not found in free state.

Question. From amongst the metals sodium, calcium, aluminium, copper and magnesium, name the metal :
(a) Which reacts with water only on boiling,
(b) Another which does not react even with steam.
Answer :
(a) Aluminium (b) Copper.

Question. What is a covalent bond ? What type of bond exists in
(a) CCl₄, (b) CaCl₂ ?
Answer :
The chemical bond formed by the sharing of electrons
between two atoms is known as a covalent bond.
(a) Covalent bonds in CCl₄, (b) Ionic bonds in CaCl₂.

Question. What is an ionic bond ? What type of bond is present in oxygen molecule ?
Answer : The chemical bond formed by the transfer of electronsfrom one atom to another is known as an ionic bond.
Covalent bond is present in an oxygen molecule.

Question. (a) Draw the electron-dot structure of a hydrogen chloride molecule.
(b) (i) Which inert gas does the H atom in HCl resemble in electron arrangement ?
(ii) Which inert gas does the Cl atom in HCl resemble in electron arrangement ?
Answer :
(a) H× Cl
(b) (i) Helium, (ii) Argon.

Question. Why is sodium chloride soluble in water but not in kerosene and petrol ?
Answer : Water is a polar solvent and sodium chloride is an ionic compound. When sodium chloride is dissolved in water, it dissociates into ions. Therefore, it dissolves in it. On the other hand, kerosene and petrol are non-polar solvents. These cannot overcome the strong electrostatic force of attraction between the ions. And hence, NaCl does not dissolve into it.

Question. State reasons for the following observations :
(a) The shining surface of some metals becomes dull when exposed to air for a long time.
(b) Zinc fails to evolve hydrogen gas on reacting with dilute nitric acid.
(c) Metal sulphides occur mainly in rocks but metal halides occur mostly in sea and lake waters.
Answer :
(a) It is because metal reacts with substances present in atmosphere to form surface compounds which make it dull.
(b) It is because dil. HNO₃ is an oxidising agent therefore zinc gives NO and not H₂ with dil. HNO₃.
(c) It is because sea water contains sodium chloride due to which metal halides are formed, whereas sulphur is found below rocks. Therefore, metal – sulphides are formed in rocks.

Question. Describe two methods for the concentration of ores.
Answer : Two methods used for separation of ores are :
(a) Froth Floatation method : This method is used generally to remove gangue from sulphide ores. First of all, the ore is powdered and a suspension in water is formed. Then collectors and froth stabilisers are added. The collectors generally used are pine oils, fatty acids etc. The function of collectors is to increase the non-wettability of the metal part of the ore and allows it to form a froth. Froth stabilizers (cresols, aniline etc.) sustain the froth. The oil wets the metal and the water wets the gangue. Paddles and air constantly stir up the suspension to create the froth. This frothy metal is skimmed off the top and dried, to recover the metal.
(b) This method is used in those cases where either ore or the impurities are of magnetic nature. In this method, the powdered impure ore in the form of thin layer is allowed to fall on a rubber belt which moves horizontally over two rollers, one of which has electromagnet attached to it. As the ore particles roll over the belt, the magnetic component in the ore gets attracted towards the magnet. It gets collected in a heap while the non–magnetic component forms a separate heap.

Question. Give the steps involved in the extraction of metals of low and medium reactivity from their respective sulphide ores.
Answer :
Sulphide ore of low reactivity metal
↓    Roasting
Metal
↓    Refining
Pure metal
Example :
Extraction of Mercury : Mercury is a metal of low reactivity. Cinnabar, i.e., mercury (II) sulphide is the ore of mercury. It is heated in air so that it is oxidised to produce mercury (II) oxide. After that, mercury oxide is reduced to obtain mercury. The following reactions are involved in this process :
2HgS + 3O₂ → 2HgO + 2SO₂.

Sulphide ore of Medium reactivity metal
↓    Roasting
Oxide of metal
↓    Reduction
Metal
↓    Refining
Pure metal

Example :
Extraction of Zinc : Zinc is in the middle of the reactivity series. It is found in the form of zinc blende which is zinc oxide. It is first heated in the presence of air to obtain zinc oxide. Zinc oxide is reduced to obtain pure zinc metal in the presence of carbon. This process can be shown by following equations. 2ZnS + 3O₂ → 2ZnO + 2SO₂ ZnO + C → Zn + CO

Question. State five uses of metals and non-metals.
Answer :
Uses of metals :
(a) Copper and aluminium metals are used to make electrical wires.
(b) Zinc is used for galvanizing iron.
(c) Iron, copper and aluminium are used to make utensils.
(d) Lead metal is used in making car batteries.
(e) Aluminium is used to make aluminium foil for packaging materials.
Uses of non-metals :
(a) Hydrogen is used in the hydrogenation of vegetable oils.
(b) Carbon is used to make electrodes of electrolytic cells and dry cells.
(c) Nitrogen is used in the manufacture of ammonia, nitric acid and fertilizers.
(d) Sulphur is used for producing sulphuric acid.
(e) Liquid hydrogen is used as rocket fuel.

Question. Give reason for the following: 
(a) Sodium metal is kept immersed in kerosene.
(b) Blue colour of copper sulphate solution disappears when some aluminium powder is added in it.
Answer : (a) Sodium metal is so reactive that it reacts vigorously with the oxygen (of air). It catches fire and starts burning when kept open in the air. Sodium metal is stored under kerosene oil to prevent its reaction with oxygen, moisture and carbon dioxide of air.
(b) When aluminium powder is put in copper sulphate solution, then the blue colour of copper sulphate solution fades gradually due to the formation of colourless aluminium sulphate solution.
3CuSO₄ (aq) + 2Al (s) Displacement⎯⎯⎯→ Al2(SO₄)₃ (aq) + 3 Cu (s)
     Blue                                                        Colourless
Since Al is more reactive than Cu, it displaces Cu from CuSO₄ solution and forms colourless Al₂(SO₄)₃.

Question. 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 : (a) No displacement reaction will occur between NaCl solution and copper metal, as copper is less reactive than sodium.
(b) Al is less reactive than Mg, so no displacement reaction will take place.
(c) Ag is less reactive than Fe, so no displacement reaction will take place.
(d) Copper metal Cu is more reactive than silver (Ag), so displacement reaction takes place.

Question. 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) Draw the circuit diagram as shown. If the bulb glows on turning the switch on with the test material, the material is likely to be a metal.
(b) This method is useful except for graphite which is a good conductor of electricity although it is a non-metal. Other non-metals are not good conductors of electric current.

Question. What are amphoteric oxides? Give two examples of amphoteric oxides. 
Answer : The oxides, which react with both acids and bases to give salt, are called amphoteric oxides.
Examples: Aluminium oxide Al₂O₃ and Zinc oxide ZnO
(i) Reaction with acid
Al2O₃     +    6HCl ⎯⎯⎯→  2AlCl₃      +     3H₂O
                                   Aluminum chloride
(ii) Reaction with base 
Al2O₃    +    2NaOH ⎯⎯⎯→   2NaAlO₂   +   H₂O
                                    Sodium aluminate

Question. Define Amphoteric oxides? Give two examples of such oxides. 
Answer : Some metal oxides show both acidic as well as basic behaviour. Those metal oxides which react with both acids as well as bases to produce salts and water are known as amphoteric oxides. For example: Aluminium oxide, Zinc oxide
Al₂O₃   +    6HCl ⎯⎯⎯→ 2AlCl₃ + 3H₂
                  (Acid)        (Salt)   (Water)
Al₂O₃   +  2NaOH ⎯⎯⎯→ 2NaAlO₂ + H₂O
                (Base)           (Salt)      (Water)

Question. 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 the figure.  9
(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) When sulphur is heated in air, sulphur dioxide gas is formed.
(i) Sulphur dioxide has no action on dry litmus paper.
(ii) Sulphur dioxide turns blue (moist) litmus paper red.
(b) S (s)     +   O₂ (g)  ⎯⎯⎯→   SO₂ (g)
    Sulphur       Oxygen           Sulphur dioxide
     SO₂       +    H₂O      ⎯⎯⎯→   H₂SO₃
                                             Sulphurous acid

Question. Give reasons:
(a) Platinum, gold and silver are used to make jewellery. (Board Question)
(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.
Answer : (a) Platinum, gold and silver are metals with a very low reactivity and they don’t show corrosion. These also have very brilliant lustre. So, these are used to make jewellery.
(b) Metals like sodium, potassium and lithium react with air (oxygen) and moisture at room temperature and readily catch fire. Hence to prevent them from accidental fire, they are stored under oil.
(c) Aluminium does not get corroded as it is covered by a protective layer of Aluminium oxide and is a very good conductor of heat.
(d) It is easier to obtain a metal from its oxide as compared to its sulphides and carbonates. So carbonate and sulphide ores are converted into metal oxides before reduction.

Question. A metal ‘M’ is found in nature as its carbonate. It is used in the galvanization of iron. Identify ‘M’ and name its ore. How will you convert this ore into free metal? 
Answer : ‘M’ = Zinc metal
Zinc occurs as Zinc Carbonate in calamine ore, ZnCO₃.
Zinc can be extracted from the ore by:
(i) Zinc Carbonate is first converted into Zinc Oxide by calcination. When calamine ore (zinc carbonate) is heated strongly in the absence of air, it decomposes to form zinc oxide and carbon dioxide.
ZnCO₃  Calcinatio⎯⎯⎯→ ZnO (s) + CO₂↑
(Calamine ore)
(ii) Zinc metal is then extracted from zinc oxide by reduction with carbon (coke).
ZnO (s)    +   C (s) ⎯⎯⎯→    Zn (s)    + CO↑
Zinc oxide     (Coke)      Zinc metal    Carbon monoxide

Question. Write down important properties of ionic compounds.
Answer : (i) Ionic compounds are generally hard and solids.
(ii) Ionic compounds have high melting and boiling points.
(iii) Ionic compounds are mostly soluble in water and insoluble in solvents like kerosene oil, alcohols, etc.
(iv) In their molten state or aqueous solution these are good conductors of electric current.

Question. (a) Why does calcium start floating when added to water? 
(b) Most of the metals do not give hydrogen while reacting with nitric acid. Why?
(c) Write equation for the reaction of iron with steam. Name the compound of iron obtained.
Answer : (a) The reaction of calcium with water is less violent. The heat evolved is not sufficient for hydrogen to catch fire.
Ca (s) + 2H₂O (l) ⎯⎯⎯→ Ca(OH)₂ (aq) + H₂ (g)
Calcium starts floating because the bubbles of hydrogen gas formed stick to the surface of the metal.
(b) Most of the metals do not give hydrogen while reacting with nitric acid because HNO3 is a strong oxidising agent. It oxidises the H2 produced to water and itself gets reduced to any of the nitrogen oxides (N₂O, NO, NO₂).
(c) Iron reacts with steam to form iron oxide and hydrogen
3Fe (s) + 4H₂O (g) ⎯⎯⎯→ Fe3O₄ (s) + 4H₂ (g)
                                 Ferro-ferric oxide

Question. Recently galvanization industry has bloomed due to extensive use of galvanization process.
(a) What is ‘galvanization’ ?
(b) Mention two areas where it is found in use.
(c) Sometimes zinc coating is broken, still the object remains protected, give reasons.
Answer :
(a) Galvanization is a method of protecting steel and iron from rusting by coating with a thin layer of zinc.
(b) Cooking utensils and industrial equipments are galvanized for their long life.
(c) In case zinc coating gets broken, the galvanized object still remains protected against rusting because zinc is more reactive than iron and hence can be easily oxidised. Thus, when zinc layer breaks down, the zinc continues to react and get oxidised. Hence, iron object remains protected.

Question. A farmer was working with an agricultural machine when he observed a crack. He realised that if the crack is not mended it will lead to further damage of the machine. He reached out to the local mechanic who repaired the crack with some iron compound and aluminium. What is the technique used by the local mechanic ? Write relevant chemical reaction equation for the same.
Answer :
The local mechanic used thermite reaction for repairing the crack in machine. In this Iron(III)oxide (Fe₂O₃) with aluminium (Al) are reacted. The reaction is accompanied by evolution of large amount of heat, which is used to melt the metal around the crack which solidifies after cooling and hence fills the crack.
Fe₂O₃(s) + 2Al(s) → 2Fe(l) + Al₂O₃(s) + Heat

Question. The metals extracted from their ores are not very pure. They contain impurities, which can be removed by the process of refining. Name the most widely used process of refining impure metals. Draw a diagram of the apparatus used for refining of copper metal and state:
(i) The name of the rods which are used as cathode and anode.
(ii) The electrolyte used during the process.
(iii) What happens to the pure metal when current passes through the electrolyte?
(iv) What happens to the soluble and insoluble impurities present in the impure copper? 
Answer : The most common method for refining of impure metals is electrolytic refining.
Electrolytic Refining of Copper:
(i) A thin strip of pure metal is made the cathode whereas impure metal is made the anode.
(ii) Aqueous solution of salt of the metal to be refined.
(iii) On passing the current through the electrolyte, pure metal from the anode dissolves into the electrolyte. An equivalent amount of pure copper metal from the electrolyte gets deposited on the cathode. Pure copper metal is collected at the cathode.
(iv) The soluble impurities go into the solution while the insoluble impurities settle down at the bottom of the anode and are known as anode mud.

Question. (a) Explain the steps for extraction of copper from its ore. Write the reaction involved. 
(b) Draw a neat, labelled diagram for electrolytic refining of copper and explain the process.
Answer : (a) Copper is found as Cu₂S in nature. The concentrated Cu₂S is roasted in presence of air and Cu₂O is formed.
2Cu₂S + 3O₂ (g) Heat ⎯⎯⎯→ 2Cu₂O (s) + 2SO₂ (g)
Copper oxide (Cu₂O) is then heated in the absence of air. This reduces Cu₂O into copper metal. The copper obtained is called blister copper because the SO2 produced during this reaction gets trapped inside its surface causing blisters to appear on the surface of copper metal. 
2Cu₂O + Cu Heat ⎯⎯⎯→ 6Cu (s) + SO₂ (g)
(b) Electrolytic refining of copper:  

Question. (a) Explain any two physical properties of ionic compounds giving reason.
(b) List any two metals found in free state in earth’s crust. Where are they located in activity series?
(c) Metals towards the top of the activity series can not be obtained from their compounds by reducing with carbon. Why? 
Answer : (a) Physical properties of ionic compounds:
(i) Ionic compounds are usually crystalline solids because their oppositely charged ions attract one another strongly and form a regular crystal structure.
(ii) Ionic compounds have high melting and high boiling points. The ionic compounds are made up of +ve and –ve ions. There is a strong force of attraction between the oppositely charged ions, so a lot of heat energy is required to break this force of attraction and melt or boil the ionic
compounds.
(b) Gold and platinum metals are found in free state in the earth’s crust. These metals are located at the bottom in the activity series.
(c) Metals towards the top of the activity series are highly reactive. The oxides of highly reactive metals are very stable and can not be reduced by ‘carbon’ to obtain free metals because these metals have more affinity for oxygen than carbon.

Question. Pure iron is soft and stretches easily when hot 
(a) How does this property of iron change when:
(i) small amount of carbon is mixed with it?
(ii) nickel and chromium are mixed with it?
(b) Define an alloy. How is an alloy prepared?
(c) An alloy has low melting point and is therefore used for electrical fuse. Name the alloy and write its constituents.
Answer : (a) (i) When small amount of carbon is mixed with iron, it becomes an alloy that is called steel. The carbon present in pig iron or cast iron makes it brittle and therefore, it cannot be used for structural purposes.
(ii) When iron is mixed with chromium and nickel, then stainless steel is obtained. Stainless steel does not rust at all.
Stainless steel is used for making cooking utensils, knives, scissors and surgical instruments etc.
(b) Alloy: An alloy is a homogeneous mixture of two or more metals or a metal and a non- metal. An alloy is generally prepared by heating the mixture of the metals (or metals and non-metals) to the molten state and then cooling the mixture to solidify at room temperature.
(c) A fuse wire is made up of an alloy of tin and copper or tin and lead (composition: 63% tin and 37% lead).

Question. (a) In the formation of compound between two atoms A and B, A loses two electrons and B gains one electron.
(i) What is the nature of bond between A and B?
(ii) Suggest the formula of the compound formed between A and B.
(b) On similar lines explain the formation of MgCl2 molecule.
(c) Common salt conducts electricity only in the molten state. Why?
(d) Why is melting point of NaCl high?
Answer : (a) A - 2e- ⎯⎯⎯→ A2+
            B +1e- ⎯⎯⎯→ B–
(b) (i) Mg has 2 electrons in its outermost shell so it loses its 2 electrons to achieve the inert gas configuration of eight valence electrons and forms positively charged ion or divalent cation.
(ii) Cl has 7 electrons in its outermost shell so it gains one electron to achieve the stable inert gas configuration and forms negatively charged ion or monovalent anion. 
(c) Common salt (NaCl) is an ionic compound which conducts electricity only in molten state because in molten state the electrostatic forces of attraction between oppositely charged ions (Na+ and Cl–) are overcome due to heat. Thus the ions move freely and conduct electricity.
(d) NaCl is an ionic compound so there is a strong force of attraction between the positively charged sodium ion and negatively charged chloride ion. Therefore a considerable amount of energy is required to break the strong interionic attraction. Thus NaCl has high melting point.

Question. (a) Show the formation of magnesium chloride and sodium chloride by transfer of electrons.
(b) Identify the ions present in these compounds.
(c) Why do ionic compounds not conduct electricity in the solid state?
Answer : (a) (i) Sodium (Na) and Magnesium (Mg) have 1 and 2 electrons respectively in the outermost shells of their atoms, so they lose their electrons to achieve the inert gas electron configuration of eight valence electrons and form positively charged ions or cations.
On the other hand Cl has seven electrons in its atom so it gains one electron to acquire inert gas configuration and forms negatively charged ion or an anion. 
(ii) NaCl contains one sodium ion [Na+] and one chloride ion [ Cl –] . . . .
MgCl₂ contains one magnesium ion [Mg2+] and two chloride ions [ Cl –] . . . .
(iii) Ionic compounds in the solid state do not conduct electricity because movement of ions in the solid state is not possible due to their rigid structure.

Question. (a) Define corrosion. 
(b) What is corrosion of iron called?
(c) How will you recognise the corrosion of silver?
(d) Why corrosion of iron is a serious problem?
(e) How can we prevent corrosion?
Answer : (a) Corrosion. Corrosion is the process in which metals are eaten up gradually by the action of air, moisture or a chemical on their surface.
(b) Rusting of iron metal is the most common form of corrosion.
(c) When silver objects are kept in air, they get tarnished and gradually turn black due to the formation of thin silver sulphide layer on their surface by the action of H2S of air.
(d) Corrosion weakens the iron and steel objects and structures such as railings, car bodies, bridges and ships, etc. and cuts short their life, therefore it is a serious problem.
(e) Methods to prevent corrosion:
— Galvanisation is a method used to protect steel and iron from rusting.
— Painting, greasing and oiling of metals is done to prevent corrosion.
— Cleaning metals regularly and carefully.

Case Study Based Questions

1. Read the following and answer any four questions :
Metals are lustrous, malleable, ductile and are good conductors of heat and electricity. They are the solids at room temperature, except mercury which is a liquid. They can form positive ions by losing electrons to non-metals. Metals combine with oxygen to form basic oxides. Different metals have different reactivities with water and dilute acids. Metals above hydrogen in the Activity series can displace hydrogen from dilute acids. A more reactive metal displaces a less reactive metal from its salt solution. Metals occur in nature as free elements or in the form of their compounds. The extraction of metals from their ores and then refining them for use is known as metallurgy. The surface of some metals, such as iron, is corroded when they are exposed to moist air for a long period of time. This phenomenon is known as corrosion. Non-metals have properties opposite to that of metals. They are neither malleable nor ductile. They are bad conductors of heat and electricity, except for graphite, which conducts electricity.

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

Question. 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) Silicon
(c) Iron
(d) Carbon
Answer : A

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

Question. Write the name of the compound, when iron is corroded?
(a) Rust: hydrated iron (III) oxide (Fe₂O₃.x.H₂O)
(b) Rust: (Fe₂O₃)
(c) Al₂O₃.2H₂O
(d) None of these
Answer : A

Question. Why copper is used to make hot water tanks and not steel (an alloy of iron)?
(a) Because copper reacts with hot water.
(b) Because copper does not reacts with cold, hot water or steam while iron reacts vigorously with hot steam and makes iron oxide.
(c) Because copper is a good conductor of heat and electricity.
(d) All of these
Answer : B

2.
S. No.   Metals              Non-metals
1.        Lustrous                Non-lustrous
2.        Hand                     Soft
3.        Ductile                   Non-ductile
4.        Malleable               Non-malleable
5.        Good conductors     Poor conductors

Question. Give one example each of metals and non-metals.
Answer : Sodium is metal and chlorine is a non-metal. 

Question. Explain ductility.
Answer : Ductility is the property of metals in which they are converted into wires.

Question. Explain malleability.
Answer : Malleability is the property of metals in which they are converted into thin sheets.

Question. What is meant by luster ?
Answer : The shiny appearance of metal is known as luster.