Metals and Non-Metals: Class 10 Science Q&A · Page 3
114 free answers on Metals and Non-Metals (Science) for Class 10 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- ScienceClass 10CBSE
A metal that exists as a liquid at room temperature is obtained by heating its sulphide in the presence of air. Identify the metal and its ore and give the reaction involved.
Soln: Mercury is the metal which is liquid at room temperature. Ore of Mercury is Cinnabar. When we heat cinnabar in atmospheric oxygen following reaction takes place. 2HgS + 3O2 2HgO + 2SO2 Mercuric oxide is again heated to get Mercury and Oxygen 2HgO heat Hg+O2
- ScienceClass 10CBSE
A metal A, which is used in thermite process, when heated with oxygen gives an oxide B, which is amphoteric in nature. Identify A and B. Write down the reactions of oxide B with HCl and NaOH.
Soln: Metal A is Aluminium and B is Al2O3 With HCl Al2O3+ 6HCl 2AlCl3+3H2O With NaOH Al2O3+2NaOH 2NaAlO2+H2O
- ScienceClass 10CBSE
What are the constituents of solder alloy? Which property of solder makes it suitable for welding electrical wires?
Soln: Solder alloy is made of Lead and aluminium. Its low melting point makes it suitable for welding electrical wires.
- ScienceClass 10CBSE
The following reaction takes place when aluminium powder is heated with MnO2 3 MnO2 (s) + 4 Al (s) → 3 Mn (l) + 2 Al2O3 (l) + Heat (a) Is aluminium getting reduced? (b) Is MnO2 getting oxidised?
Soln: In this reaction aluminium gets oxidized as oxygen gets combined with it. Since oxygen is removed from MnO2 it is getting reduced.
- ScienceClass 10CBSE
A non-metal X exists in two different forms Y and Z. Y is the hardest natural substance, whereas Z is a good conductor of electricity. Identify X, Y and Z.
Soln: X is Carbon, Y and Z are Diamond and Graphite which are allotropes of the carbon.
- ScienceClass 10CBSE
When a metal X is treated with cold water, it gives a basic salt Y with molecular formula XOH (Molecular mass = 40) and liberates a gas Z which easily catches fire. Identify X, Y and Z and also write the reaction involved.
Soln: X is Na because molecular mass of NaOH is 40. Hence Y is NaOH Z is hydrogen has which catches fire when reacts with water. 2Na+2H2O 2NaOH+H2
- ScienceClass 10CBSE
Compound X and aluminium are used to join railway tracks. (a) Identify the compound X (b) Name the reaction (c) Write down its reaction.
Soln: Answer is Fe2O3 Involved reaction is a thermite reaction which is also called as aluminothermy Fe2O3(s) + 2Al(s)→ Al2O3 (s) + 2Fe(s) + Heat Ferric oxide Aluminium Aluminium Iron
- ScienceClass 10CBSE
Generally, when metals are treated with mineral acids, hydrogen gas is liberated but when metals (except Mn and Mg), treated with HNO3 , hydrogen is not liberated, why?
Soln: HNO3 is a strong oxidizing agent. It oxidises the liberated Hydrogen into water while converting itself to nitrogen oxide.
- ScienceClass 10CBSE
Why should the metal sulphides and carbonates be converted to metal oxides in the process of extraction of metal from them?
Soln: Metal sulphides and carbonates are converted to metal oxides in the process of extraction of metal from them because metals can be obtained easier in oxide form than its sulphide or carbonate form.
- ScienceClass 10CBSE
During extraction of metals, electolytic refining is used to obtain pure metals. (a) Which material will be used as anode and cathode for refining of silver metal by this process? (b) Suggest a suitable electrolyte also. (c) In this electrolytic cell, where do we get pure silver after passing electric current?
Soln: During extraction of metals, impure metal will be used as anode and pure metal is used as cathode for refining of silver metal by this electrolytic refining. Silver Sulphate or Silver Nitrate Pure silver is obtained on cathode
- ScienceClass 10CBSE
Iqbal treated a lustrous, divalent element M with sodium hydroxide. He observed the formation of bubbles in reaction mixture. He made the same observations when this element was treated with hydrochloric acid. Suggest how can he identify the produced gas. Write chemical equations for both the reactions.
Soln: To identify the produced gas, lighted matchstick should be brought near the gas. If match stick burns with pop sound, it indicates the evolution of Hydrogen gas. M+ 2NaOH Na2MO2+ H2 With HCl M+ 2HCl MCl2+H2
- ScienceClass 10CBSE
Which of the following can undergo a chemical reaction? (a) MgSO4 + Fe (b) ZnSO4 + Fe (c) MgSO4 + Pb (d) CuSO4 + Fe
Soln: Answer is (d) CuSO4 + Fe Explanation: Iron is more reactive than copper hence it displaces copper in the reaction to form Feso4.
- ScienceClass 10CBSE
Which of the following non-metals is a liquid? (a) Carbon (b) Bromine (c) Phosphorus Sulphur
Soln: Answer is (b) Bromine
- ScienceClass 10CBSE
Electrical wires have a coating of an insulting material. The material, generally used is (a) Sulphur (b) Graphite (c) PVC All can be used
Soln: Answer is (c) PVC Explanation: Sulphur is brittle in nature, hence it can be used and Graphite is a good conductor of electricity hence it cannot be used as insulator.
- ScienceClass 10CBSE
Generally, non-metals are not conductors of electricity. Which of the following is a good conductor of electricity? (a) Diamond (b) Graphite (c) Sulphur Fullerene
Soln: Answer is (b) Graphite
- ScienceClass 10CBSE
Although metals form basic oxides, which of the following metals form an amphoteric oxide? (a) Na (b) Ca (c) Al (d) Cu
Soln: Answer is (c) Al Explanation: Oxides of Aluminum are both acidic and basic in nature. Hence aluminum oxides are amphoteric in nature.
- ScienceClass 10CBSE
The electronic configurations of three elements X, Y and Z are X — 2, 8; Y — 2, 8, 7 and Z — 2, 8, 2. Which of the following is correct? (a) X is a metal (b) Y is a metal (c) Z is a non-metal Y is a non-metal and Z is a metal
Soln: Answer is (d) Y is a non-metal and Z is a metal Explanation: Element Y has 3 electron in its outer which is electronegative in nature. Z has 2 electrons in its outermost shell hence it is electropositive. Hence it is a metal.
- ScienceClass 10CBSE
Reaction between X and Y, forms compound Z. X loses electron and Y gains electron. Which of the following properties is not shown by Z? (a) Has high melting point (b) Has low melting point (c) Conducts electricity in molten state Occurs as solid
Soln: Answer is (b) Has low melting point Explanation: Here Z is an ionic compound and Ionic compounds have melting point hence option b) is a wrong statement.
- ScienceClass 10CBSE
Which among the following alloys contain mercury as one of its constituents? (a) Stainless steel (b) Alnico (c) Solder Zinc amalgam
Soln: Answer is (d) Zinc amalgam Explanation: Zinc amalgam is an alloy of Mercury and Zinc
- ScienceClass 10CBSE
Which among the following statements is incorrect for magnesium metal? (a) It burns in oxygen with a dazzling white flame (b) It reacts with cold water to form magnesium oxide and evolves hydrogen gas (c) It reacts with hot water to form magnesium hydroxide and evolves hydrogen gas It reacts with steam to form magnesium hydroxide and evolves hydrogen gas
Soln: Answer is (b) It reacts with cold water to form magnesium oxide and evolves hydrogen gas Explanation: Magnessium reacts with cold water to form magnesium oxide and evolves hydrogen gas is a wrong statement because Magnessium Hydroxide is formed not Magnessium oxide.