{"id":36279,"date":"2022-01-04T16:41:18","date_gmt":"2022-01-04T11:11:18","guid":{"rendered":"https:\/\/mcq-questions.com\/?p=36279"},"modified":"2022-01-06T09:59:31","modified_gmt":"2022-01-06T04:29:31","slug":"mcq-questions-for-class-10-science-chapter-3","status":"publish","type":"post","link":"https:\/\/mcq-questions.com\/mcq-questions-for-class-10-science-chapter-3\/","title":{"rendered":"MCQ Questions for Class 10 Science Chapter 3 Metals and Non-metals"},"content":{"rendered":"
Question 1.<\/p>\n
(A) Na <\/p>\n Question 2.<\/p>\n (i) It does not react with water. (A) (i) and (iv) Explanation: Question 3.<\/p>\n (A) Sulphur Explanation: Question 4.<\/p>\n (A) Mg Explanation: Question 5.<\/p>\n (A) It burns in oxygen with a dazzling white flame Explanation: Question 6.<\/p>\n (A) Sulphur Explanation: <\/p>\n Question 7.<\/p>\n (A) zinc is costlier than tin Explanation: Question 8.<\/p>\n (A) Copper Explanation: Question 9.<\/p>\n (i) Cu (A) (i) and (ii) Question 10.<\/p>\n (A) Gallium Explanation: Question 11.<\/p>\n (i) Na (A) (i) and (iv) Explanation: <\/p>\n Question 12.<\/p>\n (i) positively charged cathode (A) (i) and (ii) Explanation: Question 13.<\/p>\n (A) Brass Explanation: Question 14.<\/p>\n (i) KCl (A) (i) and (ii) Explanation: Question 15.<\/p>\n (i) Au (A) (i) and (ii) Explanation: <\/p>\n Question 16.<\/p>\n (A) deposited on cathode Explanation: Assertion and Reason Based MCQs<\/span><\/p>\n Directions : In the following questions, A statement of Assertion (A) is followed by a statement of Reason (R). Mark the correct choice as. Question 1.<\/p>\n Answer: Explanation: Question 2.<\/p>\n Answer: Explanation: Question 3.<\/p>\n Answer: Explanation: Question 4.<\/p>\n Answer: Explanation: Question 5.<\/p>\n Answer: Explanation: <\/p>\n Question 6.<\/p>\n Answer: Explanation: Question 7.<\/p>\n Answer: Explanation: Case-Based MCQs<\/span> Question 1.<\/p>\n (A) A Explanation: <\/p>\n Question 2.<\/p>\n (A) A only Explanation: Question 3.<\/p>\n (A) B > A > C > D Explanation: Question 4.<\/p>\n (A) Oxygen Explanation: Hydrogen gas is produced when dilute HQ is added to a reactive metal.<\/p>\n Question 5.<\/p>\n (A) Most reactive: C; Least reactive: B Explanation: <\/p>\n II. Read the following and answer any four questions from Question l. to Question 5. Question 1.<\/p>\n (A) A-AlandC-Fe Explanation: Question 2.<\/p>\n (A) B-Fe, D – Al Explanation: Question 3.<\/p>\n (A) Metal oxides which do not react with acids but reacts with bases. Explanation: Question 4.<\/p>\n (A) Both aluminium oxide and zinc oxide Explanation: Question 5.<\/p>\n (A) Exothermic reaction Explanation: CH2<\/sub> (g) + 2O2<\/sub>(g)\u00a0 CO(g) + 2HO + Heat<\/p>\n <\/p>\n III. Read the following and answer any four questions from Question l. to Question 5.<\/p>\n Sohan 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 sad but after a futile argument, the man beat a hasty retreat.<\/p>\n Question 1.<\/p>\n (A) Hydrochloric acid Explanation: Question 2.<\/p>\n (A) Dil. HCl: Cone. HNO3<\/sub> 3:1 Explanation: Question 3.<\/p>\n (A) Aqua regia is a strong oxidising agent. Explanation: <\/p>\n Question 4.<\/p>\n (A) Gold and platinum Explanation: Question 5.<\/p>\n (A) Gold Explanation: lV. Read the following and answer any four questions from Question l. to Question 5. Question 1.<\/p>\n (A) Extraction Explanation: Question 2.<\/p>\n (i) Au (A) (i) and (ii) Explanation: <\/p>\n Question 3.<\/p>\n (A) deposited on cathode. Explanation: Question 4.<\/p>\n (A) cathode, anode Explanation: Question 5.<\/p>\n (A) negative, oxidation Explanation: V. Read the following and answer any four questions from Question l. to Question 5. Non-Metallic Character: Question 1.<\/p>\n (A) Cs>Rb>Li>Na>K Explanation: <\/p>\n Question 2.<\/p>\n (A) as Hydrogen has one electron & readily loses electron to form negative ion. Explanation: Question 3.<\/p>\n (A) F Explanation: Question 4.<\/p>\n (A) Electronegativity increases down the group due to decrease in atomic size. Explanation: <\/p>\n Question 5.<\/p>\n (A) F and Li are in the same group. Atomic size increases down the group Explanation: VI. In a thermite reaction, a compound of iron reacts with a metal.<\/p>\n Question 1.<\/p>\n (A) Zinc Explanation: Question 2.<\/p>\n (A) Zinc Explanation: Question 3.<\/p>\n (A) Fe2<\/sub>O2<\/sub>+ 2Al \u2192 2Fe + Al2<\/sub>O2<\/sub> – Heat. <\/p>\n Question 4.<\/p>\n (A) Ferrous oxide Metals and Non-metals Class 10 MCQ Questions With Answers Question 1. Which one of the following metals does not react with cold as well as hot water? (A) Na (B) Ca (C) Mg (D) Fe Answer: (D) Fe Explanation: Metals like aluminium, zinc, iron do not react with hof\/cold water. They react with water only …<\/p>\n
\n(B) Ca
\n(C) Mg
\n(D) Fe
\nAnswer:
\n(D) Fe
\nExplanation:
\nMetals like aluminium, zinc, iron do not react with hof\/cold water. They react with water only when water is in the form of steam.
\n3Fe + 4H2<\/sub>O \u2192 Fe3<\/sub>O4<\/sub> + 4H2<\/sub>.<\/p>\nWhat happens when calcium is treated with water?<\/h2>\n
\n(ii) It reacts violently with water.
\n(iii) It reacts less violently with water.
\n(iv) Bubbles of hydrogen gas formed stick to the surface of calcium.<\/p>\n
\n(B) (ii) and (iii)
\n(C) (i) and (ii)
\n(D) (iii) and (iv)
\nAnswer:
\n(D) (iii) and (iv)<\/p>\n
\nCalcium reacts slowly with water. The reaction forms calcium hydroxide, Ca(OH)2<\/sub> and hydrogen gas (H2<\/sub>). The calcium metal sinks in water and after an hour or so bubbles of hydrogen are observed, stuck to the surface of the metal.<\/p>\nGenerally, non-metals are not lustrous. Which of the following non-metal is lustrous?<\/h2>\n
\n(B) Oxygen
\n(C) Nitrogen
\n(D) Iodine
\nAnswer:
\n(D) Iodine<\/p>\n
\nIodine is a non-metal but it is lustrous.
\n<\/p>\nAn element A is soft and can be cut with a knife. This is very reactive to air and cannot be kept open in air. It reacts vigorously with water. Identify the element from the following:<\/h2>\n
\n(B) Na
\n(C) P
\n(D) Ca M
\nAnswer:
\n(B) Na<\/p>\n
\nSodium is so soft that can be cut using a knife. It reacts with oxygen or moisture present in air readily and reacts with water vigorously. Because of this sodium is stored in kerosene oil to prevent any reaction or accident.<\/p>\nWhich among the following statements is incorrect for magnesium metal?<\/h2>\n
\n(B) It reacts with cold water to form magnesium oxide and evolves hydrogen gas
\n(C) It reacts with hot water to form magnesium hydroxide and evolves hydrogen gas
\n(D) It reacts with steam to form magnesium hydroxide and evolves hydrogen gas
\nAnswer:
\n(B) It reacts with cold water to form magnesium oxide and evolves hydrogen gas<\/p>\n
\nMagnesium when reacts with water gives magnesium hydroxide and hydrogen gas and not magnesium oxide.<\/p>\nElectrical wires have a coating of an insulating material. The material, generally used is<\/h2>\n
\n(B) Graphite
\n(C) PVC
\n(D) All can be used
\nAnswer:
\n(C) PVC<\/p>\n
\nPVC is a polymer and bad conductor of electricity. It is used as an insulating material for covering electric wires. Graphite is good conductor of electricity, so cannot be used as insulating material. Sulphur is a non-metal although non-conductor of electricity but brittle in nature. So, cannot be used as insulating material.<\/p>\nFood cans are coated with tin and not with zinc because<\/h2>\n
\n(B) zinc has a higher melting point than tin
\n(C) zinc is more reactive than tin
\n(D) zinc is less reactive than tin A
\nAnswer:
\n(C) zinc is more reactive than tin<\/p>\n
\nFood cans are coated with tin and not with zinc because zinc is more reactive than tin.<\/p>\nWhich of the given metals is stored under kerosene to prevent oxidation?<\/h2>\n
\n(B) Potassium
\n(C) Magnesium
\n(D) Calcium
\nAnswer:
\n(B) Potassium<\/p>\n
\nPotassium and Sodium react vigorously with oxygen in air and catch fire. These metals are stored under kerosene oil to prevent oxidation.<\/p>\nWhich of the following metals exist in their native state in nature?<\/h2>\n
\n(ii) Au
\n(iii) Zn
\n(iv) Ag<\/p>\n
\n(B) (ii) and (iii)
\n(C) (ii) and (iv)
\n(D) (iii) and (iv)
\nAnswer:
\n(C) (ii) and (iv)
\nExplanation:
\nMetals such as gold and silver are found as native metals.<\/p>\nGalvanization is a method of protecting iron from rusting by coating with a thin layer of<\/h2>\n
\n(B) Aluminium
\n(C) Zinc
\n(D) Silver
\nAnswer:
\n(C) Zinc<\/p>\n
\nIn the process of galvanization, iron is covered by a coat of zinc. This layer of zinc prevents iron from getting rusted.<\/p>\nWhich of the following metals are obtained by electrolysis of their chlorides in molten state?<\/h2>\n
\n(ii) Ca
\n(iii) Fe
\n(iv) Cu<\/p>\n
\n(B) (iii) and (iv)
\n(C) (i) and (iii)
\n(D) (i) and (ii)
\nAnswer:
\n(D) (i) and (ii)<\/p>\n
\nSodium and calcium fall towards the top of reactivity series. Since, sodium and calcium are very reactive, these metals cannot be reduced to pure form, from their oxides or carbonates.
\nThus, sodium and calcium are obtained by the process of electrolysis of their chlorides.<\/p>\nAn electrolytic cell consists of<\/h2>\n
\n(ii) negatively charged anode
\n(iii) positively charged anode
\n(iv) negatively charged cathode<\/p>\n
\n(B) (iii) and (iv)
\n(C) (i) and (iii)
\n(D) (ii) and (iv)
\nAnswer:
\n(B) (iii) and (iv)<\/p>\n
\nPositively charged ions are called cations as they are deposited at negatively charged pole. Negatively charged ions are called anions as these are deposited at positively charged pole. That’s why the negatively charged pole is called cathode and positively charged pole is called anode.<\/p>\nAlloys are homogeneous mixtures of a metal with a metal or non-metal. Which among the following alloys contain non-metal as one of its constituents?<\/h2>\n
\n(B) Bronze
\n(C) Amalgam
\n(D) Steel
\nAnswer:
\n(D) Steel<\/p>\n
\nSteel is an alloy of iron and carbon. Mixing of carbon gives strength to iron.<\/p>\nWhich of the following are not ionic compounds?<\/h2>\n
\n(ii) Hll
\n(iii) CCl4<\/sub>
\n(iv) NaCl<\/p>\n
\n(B) (ii) and (iii)
\n(C) (iii) and (iv)
\n(D) (i) and (iii)
\nAnswer:
\n(B) (ii) and (iii)<\/p>\n
\nHC1 and CCl4<\/sub> are not ionic compounds because they are formed by sharing of electrons. These are covalent compounds.<\/p>\nMetals are refined by using different methods. Which of the following metals are refined by electrolytic refining?<\/h2>\n
\n(ii) Cu
\n(iii) Na
\n(iv) K<\/p>\n
\n(B) (i) and (iii)
\n(C) (ii) and (iii)
\n(D) (iii) and (iv)
\nAnswer:
\n(A) (i) and (ii)<\/p>\n
\nSodium and potassium are extracted by electrolytic reduction. Metals obtained after electrolytic reduction are in pure form. But, copper and gold are in impure form after extraction. Copper and gold are refined by electrolytic refining methods.<\/p>\nDuring electrolytic refining of zinc, it gets<\/h2>\n
\n(B) deposited on anode
\n(C) deposited on cathode as well as anode
\n(D) remains in the solution
\nAnswer:
\n(A) deposited on cathode<\/p>\n
\nIons of zinc are positively charged, thus while electrolytic refining of zinc, zinc is deposited at cathode (negatively charged pole).<\/p>\n
\n(A) Both A and R are true and R is the correct explanation of A.
\n(B) Both A and R are true but R is NOT the correct explanation of A.
\n(C) A is true but R is false.
\n(D) A is false and R is true.<\/p>\nAssertion (A): When a piece of copper metal is added to dilute sulphuric acid, the solution turns blue.
\nReason (R): Copper reacts with dilute sulphuric acid to form blue copper (II) sulphate solution.<\/h2>\n
\n(D) A is false and R is true.<\/p>\n
\nWhen a piece of copper metal is added to dilute sulphuric acid, then it shows no reaction at normal temperature. It is because, copper reacts only with heated sulphuric acid to form blue copper (II) sulphate solution.<\/p>\nAssertion (A): Metals are sonorous.
\nReason (R): They are generally brittle in the solid state; they break into pieces when hammered.<\/h2>\n
\n(C) A is true but R is false.<\/p>\n
\nMetals are sonorous, malleable I and ductile while non-metals are brittle.<\/p>\nAssertion (A): Gas bubbles are observed when sodium carbonate is added to dilute hydrochloric acid.
\nReason (R): Carbon dioxide is given off in the reaction.<\/h2>\n
\n(A) Both A and R are true and R is the correct explanation of A.<\/p>\n
\nGas bubbles are observed when sodium carbonate is added to dilute hydrochloric acid as CO2<\/sub> gas is released.<\/p>\nAssertion (A): A mineral is called ore, when metal is extracted from it conveniently and economically.
\nReason (R): All ores are minerals but all minerals are not ores.<\/h2>\n
\n(B) Both A and R are true but R is NOT the correct explanation of A.<\/p>\n
\nMinerals are naturally occurring chemical substances in the earth’s crust obtained by mining. But a mineral is called an ore only when the metal can be extracted from it conveniently and economically. Thus, all ores are minerals but all minerals are not ores.<\/p>\nAssertion (A): Usually the sulphide ore is converted to oxide before reduction.
\nReason (R): Reduction of oxides occurs easier.<\/h2>\n
\n(A) Both A and R are true and R is the correct explanation of A.<\/p>\n
\nUsually the sulphide ore is converted to oxide before reduction as oxides are easier to reduce.<\/p>\nAssertion (A): While the extraction of copper, one of the steps involved is Cu2<\/sub>S + 2CU2<\/sub> O \u2192 6Cu + SO2<\/sub>
\nReason (R): In this reaction Cu2<\/sub>S is the reducing agent whereas Cu2<\/sub>2O is the oxidising agent.<\/h2>\n
\n(C) A is true but R is false.<\/p>\n
\nThe Cu2+<\/sup> ion in both the compounds gets reduced while sulphur gets oxidised.<\/p>\nAssertion (A): In alumino thermite process, the metals like iron melts due to the heat evolved in the reaction.
\nReason (R): The reaction is: Fe2<\/sub>O3<\/sub> + 2Al \u2192 Al2<\/sub>O2<\/sub> + 2Fe<\/h2>\n
\n(A) Both A and R are true and R is the correct explanation of A.<\/p>\n
\nLarge amount of heat is evolved I which melts iron and can be used for welding.<\/p>\n
\nAttempt any 4 sub-parts from each question. Each sub-part carries 1 mark.
\nI. Read the following and answer any four questions from Q.l. to Q.5.
\nA student took the samples of four metals A, B, C and D and added following solutions one by one. The results obtained have been tabulated as follows:<\/p>\n\n\n
\n Metal<\/td>\n Iron (II) Sulphate<\/td>\n Copper (II) Sulphat<\/td>\n Zinc Sulphate<\/td>\n Silver Nitrate<\/td>\n<\/tr>\n \n A<\/td>\n No reaction<\/td>\n Displacement<\/td>\n <\/td>\n <\/td>\n<\/tr>\n \n B<\/td>\n Displacement<\/td>\n <\/td>\n No reaction<\/td>\n <\/td>\n<\/tr>\n \n C<\/td>\n No reaction<\/td>\n No reaction<\/td>\n No reaction<\/td>\n Displacement<\/td>\n<\/tr>\n \n D<\/td>\n No reaction<\/td>\n No reaction<\/td>\n No reaction<\/td>\n No reaction<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Choose the most reactive metal:<\/h2>\n
\n(B) B
\n(C) C
\n(D) D
\nAnswer:
\n(B) B<\/p>\n
\nB is the most reactive metal as it I displaces iron from its salt solution.<\/p>\nWhich of the following will displace Cu from its solution of sulphate:<\/h2>\n
\n(B) B only
\n(C) Both A and B
\n(D) None of the above
\nAnswer:
\n(B) B only<\/p>\n
\nB will displace Cu from CuSO4<\/sub>\u00a0 solution because B is more reactive than copper.<\/p>\nWhich is the correct decreasing order of reactivity?<\/h2>\n
\n(B) A > B > D > C
\n(C) D > B > A > C
\n(D) B > A > D > C
\nAnswer:
\n(A) B > A > C > D<\/p>\n
\nThe order of decreasing reactivity is: B > A > C > D B will displace Cu from CuSO4<\/sub> solution because B is more reactive than copper.<\/p>\nThe gas produced when dil. HCl is added to a reactive metal:<\/h2>\n
\n(B) Nitrogen
\n(C) Hydrogen
\n(D) None of the above
\nAnswer:
\n(C) Hydrogen<\/p>\nOn the basis of sequence of reactions, identify the most and least reactive elements.
\nA + BX \u2192 AX + B C + AY\u2192 CY + A<\/h2>\n
\n(B) Most reactive: B; Least reactive: C
\n(C) Most reactive: A; Least reactive: B
\n(D) Most reactive: B; Least reactive: A
\nAnswer:
\n(A) Most reactive: C; Least reactive: B<\/p>\n
\nThe most reactive metal is C and 1 the least reactive metal is B.<\/p>\n
\nWhen 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 any four questions from Question 1. to Question 5.<\/p>\nIdentify A and C?<\/h2>\n
\n(B) A-Fe and C – Al
\n(C) A – Mg and C- Al
\n(D) A – A1 and C – Cu
\nAnswer:
\n(A) A-AlandC-Fe<\/p>\n
\nA is Al, and C is Fe,O3<\/sub>
\n2Al (A) + Fe2<\/sub>O3<\/sub> \u2192 2Fe (C) + 2Al2<\/sub>O3<\/sub><\/p>\nIdentify B and D which are oxides of:<\/h2>\n
\n(B) B-Mg,D-Al
\n(C) B – Al, D-Cu
\n(D) B – Al, D – Fe
\nAnswer:
\n(B) B-Mg,D-Al<\/p>\n
\nB is Fe2<\/sub>O3<\/sub>, and D is Al2<\/sub>O3<\/sub>
\n2A1 + Fe2<\/sub>O3<\/sub> (B) \u2192 2Fe + 2A12<\/sub>O2<\/sub> (D)<\/p>\nAmphoteric oxides are:<\/h2>\n
\n(B) Metal oxides which reacts with both acids as well as bases.
\n(C) Metal oxides which reacts with acids but do not react with bases.
\n(D) Metal oxides which shows no reaction with either acids or bases.
\nAnswer:
\n(B) Metal oxides which reacts with both acids as well as bases.<\/p>\n
\nMetal oxides which react with both acids as well as bases to produce salt and water are called amphoteric oxides.
\nExamples:
\nAl2<\/sub>O3<\/sub> + 6HCl \u21922AlCl3<\/sub> + 3H2<\/sub>O
\nAl2<\/sub>O3<\/sub> + 2NaOH \u2192 2NaAlO2<\/sub> + H2<\/sub>O<\/p>\nWhich of the following is amphoteric in nature ?<\/h2>\n
\n(B) Only zinc oxide
\n(C) Only aluminium oxide
\n(D) Neither of them.
\nAnswer:
\n(A) Both aluminium oxide and zinc oxide<\/p>\n
\nAluminium oxide reacts with hydrochloric add to produce aluminium chloride (salt) and behaves as basic oxide. Similarly, it also reacts with sodium hydroxide (base) to produce sodium aluminate (salt) and behaves as addic oxide.
\nAl2<\/sub>O3<\/sub> + 6HCl \u2192 2AlCl3<\/sub> + +3H2<\/sub>O
\nAl2<\/sub>O3<\/sub> + 2NaOH \u2192 2NaAlO2<\/sub> + H2<\/sub>O
\nZinc oxide reacts with hydrochloric add to produce zinc chloride and behaves as basic oxide. Similarly, it also reacts with sodium hydroxide to produce sodium zincate and behaves as addic oxide.<\/p>\nThe reaction in which heat is generated is called as:<\/h2>\n
\n(B) Endothermic reaction
\n(C) Decomposition reaction
\n(D) Precipitation reaction
\nAnswer:
\n(A) Exothermic reaction<\/p>\n
\nReaction in which heat is released along with formation of products are called exothermic reactions..
\nExample: Burning of natural gas.<\/p>\nWhich of the following is used for dissolution of gold?<\/h2>\n
\n(B) Sulphuric acid
\n(C) Nitric acid
\n(D) Aqua regia
\nAnswer:
\n(D) Aqua regia<\/p>\n
\nAqua Regia is a mixture of concentrated HNO3 and concentrated HCl. It is used for dissolution of gold.<\/p>\nThe composition of aqua-regia is<\/h2>\n
\n(B) Cone. HCl: Dil. HNO3<\/sub> 3:1
\n(C) Cone. HCl: Cone. HNO3<\/sub> 3:1
\n(D) Dil. HCl: Dil. HNO3<\/sub> 3:1
\nAnswer:
\n(C) Cone. HCl: Cone. HNO3<\/sub> 3:1<\/p>\n
\nAqua regia is a mixture of nitric acid and hydrochloric acid, that is 3 part cone. HCl and one part cone. HNO3<\/sub> (3:1).<\/p>\nWhich of the following is incorrect?<\/h2>\n
\n(B) Aqua regia is a strong reducing agent.
\n(C) Aqua regia dissolves gold in it.
\n(D) Aqua regia is a mixture of hydrochloric acid and nitric acid.
\nAnswer:
\n(B) Aqua regia is a strong reducing agent.<\/p>\n
\nAqua Regia is a strong oxidizing agent due to the formation of NOCl (Nitrosyl chloride) and chlorine produced by reaction of two acids.<\/p>\nAqua regia dissolves:<\/h2>\n
\n(B) Gold and silver
\n(C) Platinum and silver
\n(D) Only gold
\nAnswer:
\n(A) Gold and platinum<\/p>\n
\nAqua Regia is a mixture of concentrated HNO3<\/sub> and concentrated HCl. Concentrated HNO3<\/sub> acts as a very strong oxidising agent which ionises Au atoms and Concentrated HCl produces nascent chlorine which in turn reacts with ionised Au atoms thus forming auric chloride.<\/p>\nExamples of Noble metals are:<\/h2>\n
\n(B) Silver
\n(C) Platinum
\n(D) All of the above
\nAnswer:
\n(D) All of the above<\/p>\n
\nThe noble metals are a group of metals that resist oxidation and corrosion in moist air. The noble metals are not easily attacked by adds. Gold, silver and copper are noble metals.<\/p>\n
\nDuring extraction of metals, electrolytic refining is used to obtain pure metals. During the process, the impure metal is made the anode and a thin strip of pure metal is made the cathode. The solution of the metal salt is used as an electrolyte. On passing the current through the electrolyte, the pure metal from the anode dissolves from the electrolyte. An equivalent of pure metal from the electrolyte is deposited on the cathode.<\/p>\nThe process of purification of the metal obtained after reduction, is called:<\/h2>\n
\n(B) Refining
\n(C) Froth floatation
\n(D) Electrolysis
\nAnswer:
\n(B) Refining<\/p>\n
\nRefining of metal is the process of purification of the metal obtained after reduction.<\/p>\nWhich of the metals are refined by electrolytic refining?<\/h2>\n
\n(ii) Cu
\n(iii) Na
\n(iv) K<\/p>\n
\n(B) (i) and (iii)
\n(C) (ii) and (iii)
\n(D) (ii) and (iv)
\nAnswer:
\n(A) (i) and (ii)<\/p>\n
\nMetals like Cu, Zn, Ag and Au are refined by electrolytic refining.<\/p>\nDuring electrolytic refining of zinc, it gets<\/h2>\n
\n(B) deposited on anode.
\n(C) deposited on cathode as well as anode.
\n(D) remains in the solution.
\nAnswer:
\n(A) deposited on cathode.<\/p>\n
\nIons of zinc are positively charged, thus while electrolytic refining of zinc, zinc is deposited at cathode (negatively charged pole).<\/p>\nIn electrolytic refining of copper, impure copper act as ……….. and pure copper as ………… :<\/h2>\n
\n(B) cathode, electrolyte
\n(C) anode, cathode
\n(D) electrolyte, cathode
\nAnswer:
\n(C) anode, cathode<\/p>\n
\nIn electrolytic refining of copper, anode act as impure copper while cathode is a strip of pure copper.
\nAt anode: Cu(s) Cu,2+<\/sup> (aq) + 2e–<\/sup>
\nAt cathode: Cu2<\/sub>+ (aq) + 2e–<\/sup> + Cu (s)<\/p>\nThe anode is ………….. and the reaction at the anode is………… .<\/h2>\n
\n(B) negative, reduction
\n(C) positive, oxidation
\n(D) positive, reduction
\nAnswer:
\n(C) positive, oxidation<\/p>\n
\nThe anode is positive and cathode is negative electrode. The reaction at the anode is oxidation and that at the cathode is reduction.<\/p>\n
\nMetallic Character:
\nThe ability of an atom to donate electrons and form positive ion (cation) is known as electro-positivity or metallic character. Down the group, metallic character increases due to increase in atomic size and across the period, from left to right electro\u00acpositivity decreases due to decrease in atomic size.<\/p>\n
\nThe ability of an atom to accept electrons to form a negative ion (anion) is called non-metallic character or electronegativity. The elements having high electro-negativity have a higher tendency to gain electrons and form anion.
\nDown the group, electronegativity decreases due to increase in atomic size and across the period, from left to right electro -negativity increases due to decrease in atomic size.
\n<\/p>\nWhich of the following correctly represents the decreasing order of metallic character of Alkali metals plotted in the graph?<\/h2>\n
\n(B) K>Rb>Li>Na>Cs
\n(C) Cs>Rb>K>Na>Li
\n(D) Cs>K>Rb>Na>Li
\nAnswer:
\n(C) Cs>Rb>K>Na>Li<\/p>\n
\nAs we move down the group atomic radius increases so the metallic character also increases. So, the correct sequence is : Cs>Rb>K>Na>Li<\/p>\nHydrogen is placed along with Alkali metals in the modern periodic table though it shows non-metallic character:<\/h2>\n
\n(B) as Hydrogen can easily lose one electron like alkali metals to form positive ion.
\n(C) as Hydrogen can gain one electron easily like Halogens to form negative ion.
\n(D) as Hydrogen shows the properties of non-metals,
\nAnswer:
\n(B) as Hydrogen can easily lose one electron like alkali metals to form positive ion.<\/p>\n
\nHydrogen is placed along with Alkali metals in the modern periodic table though it shows non-metallic character as Hydrogen can easily lose one electron like alkali metals to form positive ion.<\/p>\nWhich of the following has highest electronegativ-ity?<\/h2>\n
\n(B) Cl
\n(C) Br
\n(D) I
\nAnswer:
\n(A) F<\/p>\n
\nElectronegativity increases when moves towards period and decrease when toward group.<\/p>\nIdentify the reason for the gradual change in electronegativity in halogens down the group.<\/h2>\n
\n(B) Electronegativity decreases down the group due to decrease in tendency to lose electrons.
\n(C) Electronegativity decreases down the group due to increase in atomic radius\/ tendency to gain electron decreases.
\n(D) Electronegativity increases down the group due to increase in forces of attractions between nucleus & valence electrons.
\nAnswer:
\n(C) Electronegativity decreases down the group due to increase in atomic radius\/ tendency to gain electron decreases.<\/p>\n
\nElectronegativity decreases down the group due to increase in atomic radius\/ tendency to gain electron decreases.<\/p>\nWhich of the following reason correctly justifies that “Fluorine (72pm) has smaller atomic radius than Lithium (152pm)”?<\/h2>\n
\n(B) F and Li are in the same period. Atomic size increases across the period due to increase in number of shells
\n(C) F and Li are in the same group. Atomic size decreases down the group
\n(D) F and Li are in the same period and across the period atomic size\/radius decreases from left to right.
\nAnswer:
\n(D) F and Li are in the same period and across the period atomic size\/radius decreases from left to right.<\/p>\n
\nF and Li are in the same period and across the period atomic sizeadius decreases from left to right.<\/p>\nThe metal used is:<\/h2>\n
\n(B) Aluminium
\n(C) Magnesium
\n(D) None of these.
\nAnswer:
\n(B) Aluminium<\/p>\n
\nAluminium (Al) is used in thermite process. Al is the reducing agent.<\/p>\nAfter completion of this reaction, a metal is obtained in the molten state. Identify the metal:<\/h2>\n
\n(B) Aluminium
\n(C) Iron
\n(D) Magnesium
\nAnswer:
\n(C) Iron<\/p>\n
\nAl reacts with oxygen to form aluminium oxide (Al2<\/sub>2O3<\/sub>) which is amphoteric in nature.<\/p>\nThe correct equation to justify thermite reaction is:<\/h2>\n
\n(B) Fe2<\/sub>2O2<\/sub> + 2Al \u2192 2Fe + Al2<\/sub>O2<\/sub> + Heat.
\n(C) Al2<\/sub>2O2<\/sub>+ 2Fe \u2192 2Al + Fe2<\/sub>O2<\/sub>+ Heat.
\n(D) Fe2<\/sub>2O2<\/sub>+ 2Al \u2192 2Fe + A12<\/sub>O2<\/sub>.
\nAnswer:
\n(B) Fe2<\/sub>2O2<\/sub> + 2Al \u2192 2Fe + Al2<\/sub>O2<\/sub> + Heat.
\nExplanation:
\nIn the thermite process, iron (III) oxide is heated with aluminium, which results in evolution of high amount of heat which melts iron. This molten iron is used to fill the cracked machine parts. Fe2<\/sub>O3<\/sub> (s) + 2Al(s) \u2192 2Fe(l) + Al2<\/sub>O3<\/sub>\u00a0 (s) + Heat<\/p>\nThe correct name for Fe2<\/sub>O3<\/sub> is:<\/h2>\n
\n(B) Ferric oxide
\n(C) Ferrous hydroxide
\n(D) Ferric hydroxide
\nAnswer:
\n(B) Ferric oxide
\nExplanation:
\nThe correct name for Fe2<\/sub>O2<\/sub> is ferric oxide.<\/p>\nMCQ Questions for Class 10 Science with Answers<\/a><\/h4>\n","protected":false},"excerpt":{"rendered":"