--- title: "NCERT Solutions Class 10 Science Chapter 3 Metals and Non-metals" url: https://www.swavid.com/science/class/10/chapter/metals-and-non-metals/ncert-solutions dateModified: 2026-10-07T16:42:23+00:00 --- # NCERT Solutions Class 10 Science Chapter 3 Metals and Non-metals This chapter's questions cover the physical and chemical properties of metals and non-metals, their reactivity series, ionic compounds, extraction processes, and corrosion prevention. Free PDF (15 pages): https://www.swavid.com/api/seo/pdf/ncert/science/class-10/swavid-ncert-solutions-class-10-science-chapter-3-metals-and-non-metals-2a0c5beede.pdf ## QUESTIONS ### Question 1 *2 marks · Very short answer* Give an example of a metal which (i) is a liquid at room temperature. (ii) can be easily cut with a knife. (iii) is the best conductor of heat. (iv) is a poor conductor of heat. **Part (i)** 1. Mercury is the only metal that exists as a liquid at room temperature. Answer (i): Mercury **Part (ii)** 1. Sodium and potassium are alkali metals that are very soft and can be easily cut with a knife. Answer (ii): Sodium (or potassium) **Part (iii)** 1. Silver and copper are known to be the best conductors of heat. Answer (iii): Silver **Part (iv)** 1. Lead and mercury are comparatively poor conductors of heat. Answer (iv): Lead (or mercury) **Answer:** Examples of metals based on their specific physical properties are given in the parts below. > Common mistake: Confusing metals and non-metals while stating exceptions in physical properties. ### Question 2 *2 marks · Very short answer* Explain the meanings of malleable and ductile. **Solution** 1. Malleability is the property of metals by which they can be beaten into thin sheets. 2. Ductility is the ability of metals to be drawn into thin wires. **Answer:** Malleability is the ability to be beaten into thin sheets, and ductility is the ability to be drawn into thin wires. > Common mistake: Interchanging the definitions of malleability and ductility. ## QUESTIONS ### Question 1 *2 marks · Very short answer* Why is sodium kept immersed in kerosene oil? **Solution** 1. Sodium is a highly reactive metal. 2. It reacts so vigorously with oxygen and moisture in the air that it catches fire if kept in the open. 3. Therefore, it is kept immersed in kerosene oil to prevent accidental fires. **Answer:** Sodium is kept immersed in kerosene oil because it is a highly reactive metal that catches fire if exposed to air. > Common mistake: Stating that sodium reacts with water only, forgetting its vigorous reaction with oxygen in the air. ### Question 2 *3 marks · Short answer* Write equations for the reactions of (i) iron with steam (ii) calcium and potassium with water **Part (i)** 1. Iron reacts with steam to form iron(III,II) oxide and hydrogen gas. 2. $3\text{Fe}(s) + 4\text{H}_2\text{O}(g) \rightarrow \text{Fe}_3\text{O}_4(s) + 4\text{H}_2\text{O}(g)$ -> correction: $3\text{Fe}(s) + 4\text{H}_2\text{O}(g) \rightarrow \text{Fe}_3\text{O}_4(s) + 4\text{H}_2(g)$ Answer (i): $3\text{Fe}(s) + 4\text{H}_2\text{O}(g) \rightarrow \text{Fe}_3\text{O}_4(s) + 4\text{H}_2(g)$ **Part (ii)** 1. Calcium reacts with water to form calcium hydroxide and hydrogen gas. 2. $ \text{Ca}(s) + 2\text{H}_2\text{O}(l) \rightarrow \text{Ca}(\text{OH})_2(aq) + \text{H}_2(g)$ 3. Potassium reacts violently with cold water to form potassium hydroxide, hydrogen, and heat energy. 4. $2\text{K}(s) + 2\text{H}_2\text{O}(l) \rightarrow 2\text{KOH}(aq) + \text{H}_2(g) + \text{heat energy}$ Answer (ii): $\text{Ca}(s) + 2\text{H}_2\text{O}(l) \rightarrow \text{Ca}(\text{OH})_2(aq) + \text{H}_2(g)$ and $2\text{K}(s) + 2\text{H}_2\text{O}(l) \rightarrow 2\text{KOH}(aq) + \text{H}_2(g) + \text{heat energy}$ **Answer:** Chemical equations for the reactions of iron with steam and calcium/potassium with water. > Common mistake: Forgetting to balance the equations or missing physical state symbols. ### Question 3 *3 marks · Short answer* Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows. Metal | Iron(II) sulphate | Copper(II) sulphate | Zinc sulphate | Silver nitrate A | No reaction | Displacement | No reaction | B | Displacement | No reaction | No reaction | C | No reaction | No reaction | No reaction | Displacement D | No reaction | No reaction | No reaction | No reaction Use the Table above to answer the following questions about metals A, B, C and D. (i) Which is the most reactive metal? (ii) What would you observe if B is added to a solution of Copper(II) sulphate? (iii) Arrange the metals A, B, C and D in the order of decreasing reactivity. **Part (i)** 1. Metal B displaces iron from iron(II) sulphate, meaning B is more reactive than iron. 2. None of the other metals show as many successful displacement reactions. 3. Metal B is the most reactive metal among the given samples. Answer (i): Metal B is the most reactive metal. **Part (ii)** 1. Metal B displaces copper from copper(II) sulphate solution because B is more reactive than copper. 2. A displacement reaction will occur, and the blue colour of copper(II) sulphate solution will fade. Answer (ii): Displacement reaction will occur and the blue colour of copper(II) sulphate solution will fade. **Part (iii)** 1. Metal B displaces iron, so B > Fe. 2. Metal A displaces copper, so A > Cu. 3. Metal C displaces silver, so C > Ag. 4. Metal D shows no displacement reaction with any solution, so D is the least reactive. 5. Comparing their activities with various salt solutions, the decreasing order of reactivity is B > A > C > D. Answer (iii): B > A > C > D **Answer:** Answers regarding metal reactivities based on displacement reactions. > Common mistake: Confusing displacement behaviour with the order of reactivity. ### Question 4 *3 marks · Short answer* Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute $\text{H}_2\text{SO}_4$. **Solution** 1. Hydrogen gas ($\text{H}_2$) is produced when a reactive metal is added to dilute hydrochloric acid. 2. Iron reacts with dilute sulfuric acid to form iron(II) sulfate and hydrogen gas. 3. The balanced chemical equation is: $\text{Fe}(s) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{FeSO}_4(aq) + \text{H}_2(g)$. **Answer:** Hydrogen gas is produced. Equation: $\text{Fe}(s) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{FeSO}_4(aq) + \text{H}_2(g)$. > Common mistake: Writing ferric sulfate instead of ferrous sulfate (iron(II) sulfate). ### Question 5 *3 marks · Short answer* What would you observe when zinc is added to a solution of iron(II) sulphate? Write the chemical reaction that takes place. **Solution** 1. Zinc is more reactive than iron, so it displaces iron from its sulfate solution. 2. Observation: The green color of iron(II) sulfate solution fades and eventually turns colorless, and a greyish-white coating of iron metal is deposited. 3. The balanced chemical equation is: $\text{Zn}(s) + \text{FeSO}_4(aq) \rightarrow \text{ZnSO}_4(aq) + \text{Fe}(s)$. **Answer:** The green iron(II) sulfate solution turns colorless and iron metal is deposited. Equation: $\text{Zn}(s) + \text{FeSO}_4(aq) \rightarrow \text{ZnSO}_4(aq) + \text{Fe}(s)$. > Common mistake: Stating that zinc sulfate solution is green instead of colorless. ## QUESTIONS ### Question 1 *3 marks · Short answer* (i) Write the electron-dot structures for sodium, oxygen and magnesium. (ii) Show the formation of $\text{Na}_2\text{O}$ and $\text{MgO}$ by the transfer of electrons. (iii) What are the ions present in these compounds? **Part (i)** 1. Sodium (Na): $\text{Na} \cdot$ (Atomic number 11, configuration 2, 8, 1) 2. Oxygen (O): $: \ddot{\text{O}} \cdot$ (Atomic number 8, configuration 2, 6) 3. Magnesium (Mg): $\text{Mg}:$ (Atomic number 12, configuration 2, 8, 2) Answer (i): Electron-dot structures are $\text{Na} \cdot$, $: \ddot{\text{O}} \cdot$, and $\text{Mg}:$ respectively. **Part (ii)** 1. For $\text{Na}_2\text{O}$: Two sodium atoms transfer one valence electron each to one oxygen atom, forming $2\text{Na}^+$ and $: \ddot{\text{O}} :^{2-}$. 2. For $\text{MgO}$: One magnesium atom transfers its two valence electrons to one oxygen atom, forming $\text{Mg}^{2+}$ and $: \ddot{\text{O}} :^{2-}$. Answer (ii): $\text{Na}_2\text{O}$ and $\text{MgO}$ are formed by the complete transfer of valence electrons from metal atoms to oxygen. **Part (iii)** 1. The ions present in sodium oxide ($\text{Na}_2\text{O}$) are sodium ions ($\text{Na}^+$) and oxide ions ($\text{O}^{2-}$). 2. The ions present in magnesium oxide ($\text{MgO}$) are magnesium ions ($\text{Mg}^{2+}$) and oxide ions ($\text{O}^{2-}$). Answer (iii): Cations are $\text{Na}^+$ and $\text{Mg}^{2+}$, and the anion is $\text{O}^{2-}$. **Answer:** Sodium, oxygen, and magnesium form ionic compounds through the transfer of electrons, containing specific cations and anions. > Common mistake: Incorrect representation of electron dots or incorrect charges on ions. ### Question 2 *2 marks · Very short answer* Why do ionic compounds have high melting points? **Solution** 1. Ionic compounds are composed of positively and negatively charged ions held together by strong electrostatic forces of attraction. 2. A considerable amount of energy is required to break this strong inter-ionic attraction, resulting in high melting points. **Answer:** Ionic compounds have high melting points because a considerable amount of energy is required to break the strong inter-ionic electrostatic forces of attraction. > Common mistake: Writing that molecules are broken instead of inter-ionic forces. ## QUESTIONS ### Question 1 *2 marks · Very short answer* Define the following terms. (i) Mineral (ii) Ore (iii) Gangue **Part (i)** 1. The elements or compounds, which occur naturally in the earth's crust, are known as minerals. Answer (i): The elements or compounds, which occur naturally in the earth's crust, are known as minerals. **Part (ii)** 1. Minerals that contain a very high percentage of a particular metal and the metal can be profitably extracted from it are called ores. Answer (ii): Minerals from which a metal can be profitably extracted are called ores. **Part (iii)** 1. Ores mined from the earth are usually contaminated with large amounts of impurities such as soil, sand, etc., called gangue. Answer (iii): The large amounts of impurities such as soil and sand associated with ores are called gangue. **Answer:** The definitions of mineral, ore, and gangue are provided in the respective parts. > Common mistake: Confusing minerals and ores; remember that all ores are minerals, but all minerals are not ores. ### Question 2 *2 marks · Very short answer* Name two metals which are found in nature in the free state. **Solution** 1. Metals at the bottom of the reactivity series are very unreactive and are found in nature in the free state. 2. Gold and silver are two such metals found in the free state. **Answer:** Gold and silver. > Common mistake: Naming reactive metals like sodium or potassium which are found only in combined states. ### Question 3 *2 marks · Very short answer* What chemical process is used for obtaining a metal from its oxide? **Solution** 1. The chemical process used for obtaining a metal from its oxide is reduction. 2. Metal oxides are reduced to corresponding metals by using suitable reducing agents such as carbon or through electrolytic reduction. **Answer:** Reduction process. > Common mistake: Writing oxidation instead of reduction. ## QUESTIONS ### Question 1 *3 marks · Short answer* Metallic oxides of zinc, magnesium and copper were heated with the following metals. Metal | Zinc | Magnesium | Copper Zinc oxide | | | Magnesium oxide | | | Copper oxide | | | In which cases will you find displacement reactions taking place? **Solution** 1. A more reactive metal can displace a less reactive metal from its oxide. 2. According to the reactivity series, magnesium is more reactive than zinc and copper, so it will displace zinc from zinc oxide and copper from copper oxide. 3. Zinc is more reactive than copper, so it will displace copper from copper oxide, while copper cannot displace any of them. **Answer:** Displacement reactions take place when magnesium is heated with zinc oxide and copper oxide, and when zinc is heated with copper oxide. > Common mistake: Confusing the reactivity order of metals. ### Question 2 *2 marks · Very short answer* Which metals do not corrode easily? **Solution** 1. Metals placed at the bottom of the reactivity series are unreactive. 2. Gold, silver, and platinum are examples of metals that do not corrode easily. **Answer:** Metals that are placed at the bottom of the reactivity series, such as silver, gold, and platinum, do not corrode easily. > Common mistake: Confusing reactive metals like iron which corrode easily with unreactive noble metals. ### Question 3 *2 marks · Very short answer* What are alloys? **Solution** 1. An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. 2. It is prepared by first melting the primary metal and then dissolving the other elements in it in definite proportions. **Answer:** An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. > Common mistake: Forgetting to mention that alloys can contain non-metals too. ## EXERCISES ### Question 1 *1 mark · MCQ* Which of the following pairs will give displacement reactions? - NaCl solution and copper metal - $\text{MgCl}_2$ solution and aluminium metal - $\text{FeSO}_4$ solution and silver metal - $\text{AgNO}_3$ solution and copper metal. **Solution** 1. A more reactive metal displaces a less reactive metal from its salt solution. 2. Copper is less reactive than sodium and cannot displace it. 3. Aluminium is less reactive than magnesium according to the reactivity series. 4. Silver is less reactive than iron and cannot displace it from iron sulphate. 5. Copper is placed above silver in the reactivity series and can displace silver from silver nitrate solution. **Answer:** (d) $\text{AgNO}_3$ solution and copper metal. > Common mistake: Students often confuse the positions of less reactive and more reactive metals in the activity series. ### Question 2 *1 mark · MCQ* 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** 1. Grease and paint cannot be applied to cooking utensils because they burn or contaminate food when heated. 2. Zinc is toxic for food storage and cooking pans. 3. Applying a coating of tin or using materials like steel and aluminium is suitable, but among the given options, applying grease or paint is unsuitable for cooking pans, and zinc is toxic. **Answer:** (c) Applying a coating of zinc > Common mistake: Choosing 'All of the above' without considering that grease and paint cannot be used on cooking items. ### Question 3 *1 mark · MCQ* 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 - calcium - carbon - silicon - iron. **Solution** 1. Calcium reacts with oxygen to form calcium oxide ($\text{CaO}$), which is an ionic compound with a high melting point and is soluble in water forming lime water. 2. Carbon forms carbon dioxide which is a gas or forms covalent compounds, silicon forms sand which is insoluble in water. 3. Therefore, the element is calcium. **Answer:** (a) calcium > Common mistake: Confusing carbon dioxide solubility or melting point with ionic metal oxides. ### Question 4 *1 mark · MCQ* Food cans are coated with tin and not with zinc because - zinc is costlier than tin. - zinc has a higher melting point than tin. - zinc is more reactive than tin. - zinc is less reactive than tin. **Solution** 1. Zinc is more reactive than tin. 2. Food items are acidic and can react with reactive metals if they come in contact. 3. Tin is less reactive than zinc and does not react with food acids, making it safer for coating food cans. **Answer:** (c) zinc is more reactive than tin. > Common mistake: Thinking that zinc is less reactive because it is used for galvanisation of iron. ### Question 5 *3 marks · Short answer* 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. **Part (a)** 1. Use the hammer to beat the sample; if it flattens into a sheet without breaking, it is malleable (metal); if it breaks into pieces, it is brittle (non-metal). 2. Set up an electric circuit using the battery, bulb, wires, and switch, and insert the sample between the terminals; if the bulb glows, the sample is a good conductor of electricity (metal), otherwise it is a poor conductor (non-metal). Answer (a): Malleability is tested with a hammer, and electrical conductivity is tested using a battery-bulb circuit. **Part (b)** 1. These physical property tests are useful for general classification, but they are not solely sufficient because there are exceptions like graphite which conducts electricity though it is a non-metal. Answer (b): These tests are useful for general classification but have exceptions like graphite. **Answer:** Metals are malleable and conduct electricity, whereas non-metals are brittle and are bad conductors. > Common mistake: Forgetting to mention exceptions like graphite when assessing the usefulness of conductivity tests. ### Question 6 *3 marks · Short answer* What are amphoteric oxides? Give two examples of amphoteric oxides. **Solution** 1. Metal oxides that show both acidic as well as basic behaviour by reacting with both acids and bases to form salt and water are known as amphoteric oxides. 2. Examples of amphoteric oxides are aluminium oxide ($\text{Al}_2\text{O}_3$) and zinc oxide ($\text{ZnO}$). 3. Chemical equations supporting their amphoteric nature include $\text{Al}_2\text{O}_3 + 6\text{HCl} \rightarrow 2\text{AlCl}_3 + 3\text{H}_2\text{O}$ and $\text{Al}_2\text{O}_3 + 2\text{NaOH} \rightarrow 2\text{NaAlO}_2 + \text{H}_2\text{O}$. **Answer:** Amphoteric oxides react with both acids and bases to produce salt and water; examples are $\text{Al}_2\text{O}_3$ and $\text{ZnO}$. > Common mistake: Writing only basic oxides instead of amphoteric oxides, or missing the chemical equations. ### Question 7 *2 marks · Very short answer* Name two metals which will displace hydrogen from dilute acids, and two metals which will not. **Solution** 1. Metals placed above hydrogen in the reactivity series can displace hydrogen from dilute acids. 2. Two metals that displace hydrogen are magnesium (Mg) and zinc (Zn), while two metals that do not are copper (Cu) and silver (Ag). **Answer:** Magnesium and zinc displace hydrogen from dilute acids, whereas copper and silver do not. > Common mistake: Listing copper as a metal that reacts with dilute acids. ### Question 8 *3 marks · Short answer* In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte? **Solution** 1. In the electrolytic refining of a metal M, the impure metal M is made the anode. 2. A thin strip of pure metal M is made the cathode. 3. A soluble salt solution of the metal M is used as the electrolyte. **Answer:** Anode: Impure metal M, Cathode: Strip of pure metal M, Electrolyte: Solution of a salt of metal M. > Common mistake: Interchoosing the roles of anode and cathode. ### Question 9 *3 marks · Short answer* 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. **Part (a)(i)** 1. Dry litmus paper shows no change in colour with sulphur dioxide gas because moisture is required to produce hydrogen ions. Answer (a)(i): No change in colour. **Part (a)(ii)** 1. Moist blue litmus paper turns red because sulphur dioxide dissolves in water to form an acidic solution. Answer (a)(ii): Turns red. **Part (b)** 1. Sulphur burns in air to form sulphur dioxide gas: 2. $\text{S(s)} + \text{O}_2\text{(g)} \xrightarrow{\text{Heat}} \text{SO}_2\text{(g)}$ Answer (b): $\text{S(s)} + \text{O}_2\text{(g)} \xrightarrow{\text{Heat}} \text{SO}_2\text{(g)}$ **Answer:** Sulphur dioxide gas turns moist blue litmus red and forms sulphurous acid. > Common mistake: Stating that dry litmus paper turns red with acidic gases. ### Question 10 *2 marks · Very short answer* State two ways to prevent the rusting of iron. **Solution** 1. Rusting of iron requires both oxygen and moisture. 2. Two ways to prevent the rusting of iron are painting and galvanisation. **Answer:** Painting and galvanisation are two ways to prevent the rusting of iron. > Common mistake: Forgetting to mention specific methods like oiling or painting. ### Question 11 *2 marks · Very short answer* What type of oxides are formed when non-metals combine with oxygen? **Solution** 1. Non-metals combine with oxygen to form covalent oxides. 2. These oxides are either acidic or neutral in nature. **Answer:** Non-metals form acidic or neutral oxides when they combine with oxygen. > Common mistake: Writing that non-metals form basic oxides. ### Question 12 *3 marks · Short answer* 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. **Part (a)** 1. Platinum, gold, and silver are very unreactive metals that do not corrode or tarnish easily in air, maintaining their lustre. Answer (a): They are highly unreactive and resistant to corrosion. **Part (b)** 1. Sodium, potassium, and lithium are extremely reactive metals that catch fire spontaneously if kept in open air or water. Answer (b): They react violently with air and moisture and are stored under kerosene to prevent accidental fires. **Part (c)** 1. Aluminium forms a thin, protective oxide layer on its surface when exposed to air, which prevents further corrosion and is a good conductor of heat. Answer (c): The protective oxide layer prevents further corrosion and it has high thermal conductivity. **Part (d)** 1. It is much easier to reduce a metal oxide to its corresponding metal than to reduce a sulphide or carbonate ore directly. Answer (d): Metal oxides are easier to reduce than metal sulphides or carbonates. **Answer:** Metals possess unique properties of corrosion resistance, reactivity, and protective oxide layer formation. > Common mistake: Writing incomplete reasons for storing sodium under kerosene. ### Question 13 *3 marks · Short answer* 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. **Solution** 1. Copper vessels get tarnished due to the formation of a green coating of basic copper carbonate on exposure to moist air. 2. Lemon or tamarind juice contains acids which dissolve this basic copper carbonate coating. 3. As a result, the shining brown surface of the copper vessel is restored. **Answer:** Lemon or tamarind juice contains acids that neutralize and dissolve the basic copper carbonate coating on tarnished copper vessels, cleaning them. > Common mistake: Writing that copper reacts with acid instead of realizing the acid dissolves the basic copper oxide/carbonate layer. ### Question 14 *3 marks · Short answer* Differentiate between metal and non-metal on the basis of their chemical properties. **Solution** 1. Metals form basic or amphoteric oxides, whereas non-metals form acidic or neutral oxides. 2. Metals lose electrons to form positive ions (cations), whereas non-metals gain electrons to form negative ions (anions). 3. Metals displace hydrogen from dilute acids (if they are above hydrogen in the reactivity series), whereas non-metals do not displace hydrogen from dilute acids. **Answer:** Metals form basic oxides, act as reducing agents by losing electrons, and displace hydrogen from dilute acids. Non-metals form acidic/neutral oxides and gain electrons. > Common mistake: Confusing physical properties like malleability and ductility with chemical properties. ### Question 15 *3 marks · Short answer* 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? **Solution** 1. The solution used by the fake goldsmith was aqua regia, which is a freshly prepared mixture of concentrated hydrochloric acid and concentrated nitric acid in the ratio of $$3:1$$. 2. Aqua regia is a highly corrosive, fuming liquid that is capable of dissolving gold. 3. When the gold bangles were dipped in aqua regia, the outer layer of gold got dissolved, making them sparkle like new, but drastically reducing their weight. **Answer:** The solution used was aqua regia ($3:1$ mixture of concentrated $\text{HCl}$ and $\text{HNO}_3$), which dissolves gold and reduces the weight of the ornaments. > Common mistake: Stating that dilute hydrochloric acid alone can dissolve gold. ### Question 16 *3 marks · Short answer* Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron). **Solution** 1. Copper does not react with water or steam even at high temperatures. 2. Steel is an alloy of iron, and iron reacts readily with steam and moist air to form rust. 3. Therefore, copper is suitable for making hot water tanks, whereas steel would corrode easily. **Answer:** Copper is used for making hot water tanks because it does not react with water or steam, whereas steel (an alloy of iron) rusts easily when exposed to hot water and steam. > Common mistake: Stating that copper has a higher melting point than steel as the main reason for hot water tanks. ## Frequently asked questions ### How many total questions are covered in the NCERT solutions for Class 10 Science Chapter 3 Metals and Non-metals on SwaVid? This chapter page includes 15 in-text questions divided across various sub-topics along with 16 comprehensive exercise questions. You can access SwaVid's free PDF and step-by-step solutions on this page only to practice all of them. ### Which specific topics are covered in the in-text and exercise questions of this chapter? The questions cover important concepts like the physical properties of metals, the reactivity series, displacement reactions, and electron-dot structures for ionic compounds. Other topics include metallurgy, corrosion, alloys, and the action of aqua regia on gold. ### What are the hardest question types in Class 10 Metals and Non-metals, and how should I approach them? Questions on electron-dot structures, ionic compound formation, and chemical reactions like metal-acid interactions are often considered tricky. To approach these, you should first clearly write down the electronic configurations and balance the chemical equations step by step. ### How can I write answers in my board exams to score full marks for this Science chapter? To score full marks, always define key terms clearly, write balanced chemical equations with physical states, and highlight exceptions like sodium or mercury. Referring to the detailed step-by-step solutions provided in SwaVid's free PDF on this page will help you structure your answers properly. ### Is the free PDF for Class 10 Science Chapter 3 available for download on SwaVid? Yes, SwaVid provides a completely free PDF containing detailed chapter solutions for your 2026-27 session preparation. You can easily find and download these step-by-step solutions directly on this page. ## Related pages - [Metals and Non-metals: CBSE previous year questions](https://www.swavid.com/cbse/class-10/science/pyq/metals-and-non-metals) - [Class 10 Science chapters](https://www.swavid.com/science/class/10) Solutions written by SwaVid, a personal AI tutor for Class 6 to 10 Maths and Science. Practise this chapter free: https://www.swavid.com/start/student