In this article you will get CBSE Class 10 Science chapter 1, Chemical Reactions and Equations: NCERT Exemplar Problems and Solutions (Part-III). Every question has been provided with a detailed explanation. All the questions given in this article are very important to prepare for CBSE Class 10 Board Exam.
Multiple Choice Questions (MCQs)
Question 1. Which of the following is not a physical change?
(a) Boiling of water to give water vapour
(b) Melting of ice to give water
(c) Dissolution of salt in water
(d) Combustion of Liquefied Petroleum Gas (LPG)
Answer. (d)
Explanation: A physical change involves only change in physical state whereas a chemical change results the formation of new substances. Boiling of water, melting of ice and dissolution of salt are physical changes as no new products are formed.
Question 2. The following reaction is an example of a
4NH3 (g) + 5O2 (g) → 4NO (g) + 6 H2O (g)
1. Displacement reaction
2. Combination reaction
3. Redox reaction
4. Neutralisation reaction
(a) 1 and 4
(b) 2 and 3
(c) 1 and 3
(d) 3 and 4
Answer. (c)
Explanation: A Redox reaction is combination of oxidation (removal of hydrogen) and reduction (addition of hydrogen). Displacement reaction involves displacement of some part of a compound with other atom like H atoms of NH3 are displaced by oxygen.
NCERT Solutions for CBSE Class 10 Science
Question 3. Which of the following statements about the given reaction are correct?
3Fe(s) + 4H2O(g) → Fe3O4 (s) + 4H2 (g)
1. Iron metal is getting oxidized.
2. Water is getting reduced.
3. Water is acting as reducing agent.
4. Water is acting as oxidizing agent.
(a) 1, 2 and 3
(b) 3 and 4
(c) 1, 2 and 4
(d) 2 and 4
Answer. (c)
Explanation: Addition of oxygen to Fe is an oxidation process whereas lose of oxygen from H2O to H2 is a reduction step. Since water is source of oxygen therefore it acts as oxidizing agent.
Question 4. Which of the following are exothermic processes?
1. Reaction of water with quick lime
2. Dilution of an acid
3. Evaporation of water
4. Sublimation of camphor (crystals)
(a) 1 and 2
(b) 2 and 3
(c) 1 and 4
(d) 3 and 4
Answer. (a)
Explanation: Energy is released in exothermic reactions in the form of heat.
Question 5. Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is (are) correct?
1. In beakers A and B, exothermic process has occurred.
2. In beakers A and B, endothermic process has occurred.
3. In beaker C, exothermic process has occurred.
4. In beaker C, endothermic process has occurred.
(a) Only 1
(b) Only 2
(c) 1 and 4
(d) 2 and 3
Answer. (c)
Explanation: For an exothermic reaction, heat releases during reaction so temperature increases whereas endothermic reactions proceed with absorption of heat which decrease the temperature of reaction.
Question 6. A dilute ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation?
(a) KMnO4 is an oxidizing agent, it oxidizes FeSO4
(b) FeSO4 acts as an oxidizing agent and oxidizes KMnO4
(c) The colour disappears due to dilution, no reaction is involved
(d) KMnO4 is an unstable compound and decomposes in the presence of FeSO4 to a colourless compound
Answer. (a)
Explanation: Potassium permanganate (KMnO4) acts as good oxidizing agent in acidic medium and reduces itself to manganese (II) cations, Mn2+. It oxidizes FeSO4 to Fe2(SO4)3.
Question 7. Which among the following is (are) double displacement reaction(s)?
(a) (i) and (iv)
(b) Only (ii)
(c) (i) and (ii)
(d) (iii) and (iv)
Answer. (b)
Explanation: A double displacement reaction involves displacement of two ions of two different compounds that results the formation of new compounds.
Question 8. Which among the following statement(s) is /are true? Exposure of silver chloride to sunlight for a long duration turns grey due to-
(i) The formation of silver by decomposition of silver chloride.
(ii) Sublimation of silver chloride.
(iii) Decomposition of chlorine gas from silver chloride.
(iv) Oxidation of silver chloride.
(a) (i) Only
(b) (i) and (iii)
(c) (ii) and (iii)
(d) Only (iv)
Answer. (a)
Explanation: In the presence of sunlight, AgCl decompose to form grayish white silver metal and releases chlorine gas.
Question 9. Solid calcium Oxide reacts vigorously with water to form calcium hydroxide accompanied by liberation of heat. This process is called slaking of lime. Calcium hydroxide dissolves in water to form its solution called lime water. Which among the following is are true about slaking of lime and the solution formed?
(i) It is an endothermic reaction.
(ii) It is exothermic reaction.
(iii) The pH of the resulting solution will be more than seven.
(iv) The pH of the resulting solution will be less than seven.
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (iii) and (iv)
Answer. (b)
Explanation: The formation of calcium hydroxide from calcium oxide and water with heat so it is an exothermic reaction. Calcium hydroxide is a basic compound so pH will be more than 7.
Question 10. Barium chloride on reacting with ammonium sulphate forms barium sulphate and ammonium chloride. Which of the following correctly represents the type of the reaction involved?
(i) Displacement reaction
(ii) Precipitation reaction
(iii) Combination reaction
(iv) Double displacement reaction
(a) Only (i)
(b) Only (ii)
(c) Only (iv)
(d) (ii) and (iv)
Answer. (d)
Explanation: Double displacement reaction involves displacement of cation and anions of two different compounds. In given reaction, precipitate of barium sulphate is formed.
Question 11. Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is
(a) 1 : 1
(b) 2 : 1
(c) 4 : 1
(d) 1 : 2
Answer. (b)
Explanation: The balance chemical equation for electrolysis of water is;
Question 12. Which of the following is (are) an endothermic process(es)?
(i) Dilution of sulphuric acid
(ii) Sublimation of dry ice
(iii) Condensation of water vapours
(iv) Evaporation of water
(a) Both (i) and (iii)
(b) Only (ii)
(c) Only (iii)
(d) Both (ii) and (iv)
Answer. (d)
Explanation: An endothermic process involves absorption of heat such as sublimation and evaporation needs heat energy.
Question 13. In the double displacement reaction between aqueous potassium iodide and aqueous lead nitrate, a yellow precipitate of lead iodide is formed. While performing the activity if lead nitrate is not available, which of the following can be used in place of lead nitrate?
(a) Lead sulphate (insoluble)
(b) Lead acetate
(c) Ammonium nitrate
(d) Potassium sulphate
Answer. (b)
Explanation: For the formation of lead iodide some soluble salt of lead is required like lead acetate which will form lead iodide with potassium acetate.
Question 14. Which of the following gases can be used for storage of fresh sample of an oil for a long time?
(a) Carbon dioxide or oxygen
(b) Nitrogen or oxygen
(c) Carbon dioxide or helium
(d) Helium or nitrogen
Answer. (d)
Explanation: Inert gases like Helium and Nitrogen can be used for storage of food items as they prevent the oxidation of food items.
Question 15. The following reaction is used for the preparation of oxygen gas in the laboratory
Which of the following statement(s) is/are correct about the reaction?
(a) It is a decomposition reaction and endothermic in nature
(b) It is a combination reaction
(c) It is a decomposition reaction and accompanied by release of heat
(c) It is a photochemical decomposition reaction and exothermic in nature
Answer. (a)
Explanation: Decomposition reaction can be defined as the reaction which involves decomposition of one compound to more than one substance. Endothermic reactions require heat energy to form products.
Question 16. Which one of the following processes involve chemical reactions?
(a) Storing of oxygen gas under pressure in a gas cylinder
(b) Liquefaction of air
(c) Keeping petrol in a China dish in the open
(d) Heating copper wire in the presence of air at high temperature
Answer. (d)
Explanation: Chemical changes involve formation of new compounds from one of more substances. Reaction of copper wire with oxygen forms copper (II) oxide.
Question 17. In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature?
(a) 2H2 (l) + O2 (l) → 2H2O (g)
(b) 2H2 (g) + O2 (l) → 2H2O (g)
(c) 2H2 (g) + O2 (g) → 2H2O (l)
(d) 2H2 (g) + O2 (g) → 2H2O (g)
Answer. (c)
Explanation: At standard conditions, hydrogen and oxygen exist in gaseous state whereas water in liquid state.
Question 18. Which of the following are combination reactions?
(a) Both (i) and (iii)
(b) Both (iii) and (iv)
(c) Both (ii) and (iv)
(d) Both (ii) and (iii)
Answer. (d)
Explanation: Combination reactions form a new product with the combination of more than one reactant molecules.
Question 19. Write the balanced chemical equations for the following reactions and identify the type of reaction in each case.
(a) Nitrogen gas is treated with hydrogen gas in the presence of a catalyst at 773 K to form ammonia gas.
(b) Sodium hydroxide solution is treated with acetic acid to form sodium acetate and water.
(c) Ethanol is warmed with ethanoic acid to form ethyl acetate in the presence of concentrated H2SO4.
(d) Ethane is burnt in the presence of oxygen to form carbon dioxide, water and releases heat and light.
Answer.
This is an example of combination reaction.
(b) NaOH (aq) + CH3COOH (l) → CH3COONa (aq) + H2O (l)
This is an example of neutralization reaction as well as double displacement reaction.
This is an example of double displacement reaction and also called as esterification.
(d) 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g)
This is an example of combustion reaction.
CBSE Class 10 Science Syllabus 2017-2018
Question 20. Write the balanced chemical equation for the following reactions and identify the type of reaction in each case.
(a) In Thermite reaction, iron (III) oxide reacts with aluminium and gives molten iron and aluminium oxide.
(b) Magnesium ribbon is burnt in an atmosphere of nitrogen gas to form solid magnesium nitride.
(c) Chlorine gas is passed in an aqueous potassium iodide solution to form potassium chloride solution and solid iodine.
(d) Ethanol is burnt in air to form carbon dioxide, water and releases heat.
Answer.
Question 21. Complete the missing components/variables given as X and Y in the following.
Question 22. Which among the following changes are exothermic or endothermic in nature?
(a) Decomposition of ferrous sulphate
(b) Dilution of sulphuric acid
(c) Dissolution of sodium hydroxide in water
(d) Dissolution of ammonium chloride in water
Answer.
(a) Decomposition of ferrous sulphate absorbs heat during reaction therefore it is an example of endothermic reaction.
(b) When we dissolve sulphuric acid in water, large amount of heat is liberated so it is an exothermic reaction.
(c) When we dissolve sodium hydroxide in water, large amount of heat is liberated so it is an exothermic reaction.’
(d) Mixing of ammonium chloride in water absorbs heat from reaction mixture therefore it is an example of endothermic reaction.
Question. 23 Identify the reducing agent in the following reactions.
(a) 4NH3 + 5O2 → 4NO + 6H2O
(b) 2H2O + 2F2 → 4HF + O2
(c) Fe2O3 + 3CO → 2Fe + 3CO2
(d) 2H2 + O2 → 2H2O
Answer.
(a)NH3 is the reducing agent as it gives hydrogen to O2.
(b) H2O is the reducing agent.
(c) CO is a reducing agent.
(d) H2 is the reducing agent.
Question. 24 Identify the oxidizing agent (oxidant) in the following reactions.
(a) Pb3O4 + 8HCl → 3PbCl2 + Cl2 + 4H2O
(b) 2Mg + O2 → 2MgO
(c) CuSO4 + Zn → Cu + ZnSO4
(d) V2O5 + 5Ca → 2V + 5CaO
(e) 3Fe + 4H2O → Fe3O4 + 4H2
(f) CuO + H2 → Cu + H2O
Answer.
(a) Since Pb3O4 gives oxygen so it is an oxidizing agent (oxidant).
(b) Since O2 provides oxygen so it is oxidant.
(c) CuSO4 is the oxidizing agent because it gets reduces to Cu.
(d) V2O5 has been reduced to V so it will be the oxidant.
(e) H2O is the oxidant as it is reduced to H2.
(f) CuO is the oxidant as it is reduced to Cu.
Question. 25 Write the balanced chemical equations for the following reactions.
(a) Sodium carbonate on reaction with hydrochloric acid in equal molar concentrations gives sodium chloride and sodium hydrogen carbonate.
(b) Sodium hydrogen carbonate on reaction with hydrochloric acid gives sodium chloride, water and liberates carbon dioxide.
(c) Copper sulphate on treatment with potassium iodide precipitates cuprous iodide (Cu2I2), liberates iodine gas and also forms potassium sulphate.
Answer.
(a) Na2CO3(s) + HCl (aq) → NaCl (aq) + NaHCO3 (aq)
(b) NaHCO3 (s) + HCl (aq) → NaCl (aq) + H2O(l) + CO2 (g)
(c) 2CuSO4 (s) + 4KI (aq) → Cu2I2 (s) + I2 (g) + 2K2SO4 (aq)
Question. 26 A solution of potassium chloride when mixed with silver nitrate solution, an insoluble white substance is formed. Write the chemical reaction involved and also mention the type of the chemical reaction.
Answer.
The solution of KCl with AgNO3 form white precipitate of AgCl. This is a double displacement reaction.
KCl (aq) + AgNO3 (aq) → AgCl (s) + KNO3 (aq)
Question. 27 Ferrous sulphate decomposes with the evolution of a gas having a characteristic odour of burning sulphur. Write the chemical reaction involved and identify the type of reaction.
Answer.
2FeSO4 (s) → Fe2O3 (s) + SO2 (g) + SO3 (g)
The heating of ferrous sulphate gives ferric oxide and mixture of sulphur dioxide and sulphur trioxide gas. This is an example of thermal decomposition reaction and the odour of burning sulphur is due to SO2 gas.
Question. 28 Why do fire flies glow at night?
Answer.
Fire flies have a luminous bag which contains a protein; luciferin. The oxidation of luciferin occurs in the presence of luciferare enzyme with emission of light which occurs due to oxidation of magnesium. Hence they glow at night.
Question. 29 Grapes hanging on the plant do not ferment but after being plucked from the plant can be fermented. Under what conditions do these grapes ferment? Is it a chemical or a physical change?
Answer.
After plucking grapes from plants, fermentation of sugar is carried out in the presence of yeast which changes sugar to ethanol and carbon dioxide. This process occurs in the absence of oxygen means in anaerobic conditions.
Whereas grapes attach to plant involve in aerobic respiration and no fermentation can be possible under aerobic conditions.
Here fermentation is a chemical change as it results the formation of new substances; alcohol and carbon dioxide.
Question. 30 Which among the following are physical or chemical changes?
(a) Evaporation of petrol
(b) Burning of Liquefied Petroleum Gas (LPG)
(c) Heating of an iron rod to red hot
(d) Curdling of milk
(e) Sublimation of solid ammonium chloride
Answer.
(a) Physical change
(b) Chemical change
(c) Physical change
(d) Chemical change
(e) Physical change
Question. 31 During the reaction of some metals with dilute hydrochloric acid, following observations were made.
(a) Silver metal does not show any change.
(b) The temperature of the reaction mixture rises when aluminium (Al) is added.
(c) The reaction of sodium metal is found to be highly explosive.
(d) Some bubbles of a gas are seen when lead (Pb) is reacted with the acid Explain these observations giving suitable reasons.
Answer.
(a)The reactivity of silver is very low as it is placed below hydrogen in reactivity series so it does not react with dilute hydrochloric acid.
(b) Aluminium reacts with dilute HCl to form Aluminium chloride with hydrogen gas. It is an exothermic reaction so temperature of reaction mixture rises.
(c) Sodium is an alkali metal which is one of the most reactive metals and readily reacts with dilute HCl to form NaCl and hydrogen gas. The evolution of hydrogen gas cause explosion.
(d) Reaction of lead metal with dilute HCl forms lead (II) chloride and releases hydrogen gas in the form of bubbles. Since reaction is quite slow due to less reactivity of lead, only bubbles of H2 are seen to evolve.
Question. 32 A substance X,which is an oxide of a group 2 element, is used intensively in the cement industry. This element is present in bones also. On treatment with water it forms a solution which turns red litmus blue. Identify X and also write the chemical reactions involved.
Answer.
The substance X is calcium oxide (CaO) which is also known as quick lime. Reaction of quick lime with water forms calcium hydroxide. It is an alkaline solution and easily turns red litmus to blue.
.PNG "NCERT Exemplar Solution for CBSE Class 10 Science: Chemical Reactions and Equations")
Question. 33 Write a balanced chemical equation for each of the following reactions and also classify them.
(a) Lead acetate solution is treated with dilute hydrochloric acid to form lead chloride and acetic acid solution.
(b) A piece of sodium metal is added to absolute ethanol to form sodium ethoxide and hydrogen gas.
(c) Iron (III) oxide on heating with carbon monoxide gas reacts to form solid iron and liberates carbon dioxide gas.
(d) Hydrogen sulphide gas reacts with oxygen gas to form solid sulphur and liquid water.
Answer.
(a) Pb(CH3COO)2 (aq) + 2HCl (dil) → PbCl2 (s) ↓ + 2CH3COOH (aq)
This is a double displacement and a precipitation reaction.
(b) 2C2H5OH (l) + 2Na (s) → 2C2H5O−Na+ + H2↑
This is a displacement reaction.
(c) Fe2O3 (s) + 3CO(g) → 2Fe (s) + 3CO2 (g)↑
This is an example of Redox reaction.
(d) 2H2S (g) + O2 (g) → 2S (s) + 2H2O (l)
This is an example of Redox reaction.
Question. 34 Why do we store silver chloride in dark coloured bottles?
Answer.
Silver chloride can decompose in the presence of light to form silver metal therefore it must store in dark coloured bottles which can interrupt the path of light and prevent the decomposition of silver chloride.
The photochemical decomposition of silver chloride is shown below;
.PNG "NCERT Exemplar Solution for CBSE Class 10 Science: Chemical Reactions and Equations")
Question. 35 Balance the following chemical equation and identify chemical reaction the type of chemical reaction.
.PNG "NCERT Exemplar Solution for CBSE Class 10 Science: Chemical Reactions and Equations")
Question. 36 A magnesium ribbon is burnt in oxygen to give a white compound Xaccompanied by emission of light. If the burning ribbon is now placed in an atmosphere of nitrogen, it continues to burn and forms a compound Y.
(a) Write the chemical formulae of Xand Y.
(b) Write a balanced chemical equation, when X is dissolved in water.
Question. 37 Zinc liberates hydrogen gas when reacted with dilute hydrochloric acid, whereas copper does not. Explain, why?
Answer.
Zinc is placed above hydrogen in reactivity series therefore it can replace hydrogen from HCl and form hydrogen gas.
.PNG "NCERT Exemplar Solution for CBSE Class 10 Science: Chemical Reactions and Equations")
Whereas copper is placed below hydrogen in reactivity series therefore it cannot replace hydrogen from dilute acid and does not release hydrogen gas from dilute hydrochloric acid.
Cu + HCl → No reaction
Question. 38 A silver article generally turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining.
(a) Why do silver articles turn black when kept in the open for a few days? Name the phenomenon involved.
(b) Name the black substance formed and gives its chemical formula.
Answer.
(a) The metal surface of silver article reacts with atmospheric sulphur compounds like hydrogen sulphide and form black layer of sulphides. This phenomenon is called as corrosion or tarnishing of silver.
(b) The black substance that is formed by the reaction of hydrogen sulphide and atmospheric oxygen is silver sulphide (Ag2S).
4Ag + O2 + 2H2S → 2Ag2S + 2H2O
Question. 39 On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper oxide (black), oxygen gas and a brown gas X is formed.
(a) Write a balanced chemical equation of the reaction.
(b) Identify the brown gas X evolved.
(c) Identify the type of reaction.
(d) What could be the pH range of aqueous solution of the gas X?
Answer.
(b) X is nitrogen dioxide gas (NO2) that is evolved as brown, choking fumes.
(c) A thermal decomposition reaction.
(d) The aqueous solution of the NO2 forms nitrous acid and nitric acid so pH of solution would be less than 7 as medium will be acidic.
NCERT Solutions for CBSE Class 10 Science
Question. 40 Give the characteristic tests for the following gases.
(a) CO2
(b) SO2
(c) O2
(d) H2
Answer.
(a) CO2 gas: When CO2 gas is passed through lime water; it forms insoluble calcium carbonate which turns the solution milky. This is called as lime water test.
The solution becomes clear in excess of CO2 because of formation of soluble calcium bicarbonate.
(b) SO2 gas:
Due to acidic nature, sulphur dioxide gas turns moist litmus paper from blue to red. It also changes the orange colour of acidified potassium dichromate solution to green.
(c) O2 gas:
Oxygen gas burns brightly with wooden splinter that proves the combustible nature of oxygen gas.
(d) H2 gas: In the presence of atmospheric oxygen, hydrogen gas burns with a poping sound.
CBSE Class 10 Science Syllabus 2017-2018
Question. 41 What happens when a piece of
(a) Zinc metal is added to copper sulphate solution?
(b) Aluminium metal is added to dilute hydrochloric acid?
(c) Silver metal is added to copper sulphate solution?
Also, write the balanced chemical equation, if reaction occurs.
Answer.
(a) When zinc metal is added to copper sulphate solution, the colour of CuSO4 solution disappears and colourless zinc sulphate solution is formed. Solid brown copper is deposited as it displaces by Zn.
(b) Aluminium displaces hydrogen from HCl and hydrogen gas is evolved with soluble aluminium chloride.
(c) Silver is a Nobel metal and does not exhibit any reaction with copper sulphate.
Question. 42 What happens when zinc granules are treated with dilute solution of H2SO4, HCl, HNO3, NaCl and NaOH, also write the chemical equations, if reaction occurs?
Answer.
Dilute H2SO4: Zn reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas.
Dilute HCl: Zn reacts with HCl and form zinc chloride with evolution of hydrogen gas.
Dilute HNO3: Zinc reacts with cold and dilute nitric acid and form zinc nitrate, water and nitric oxide.
3Zn(s) + 8 HNO3 (aq) → 3Zn (NO3)2(aq) + 4H2O (l) + 2NO (g)
NaCI solution: No reaction will take place as sodium is more reactive than Zn and cannot replace by it.
Zn (s) + NaCl (aq) → No reaction
NaOH solution: Zinc reacts with NaOH solution and form sodium tetrahydroxidozincate and hydrogen gas.
Zn + 2 NaOH + 2 H2O → Na2[Zn(OH)4] + H2
Question. 43 On adding a drop of barium chloride solution to an aqueous solution of sodium sulphite, white precipitate is obtained.
(a) Write a balanced chemical equation of the reaction involved.
(b) What other name can be given to this precipitation reaction?
(c) On adding dilute hydrochloric acid to the reaction mixture, white precipitate disappears. Why?
Answer.
(a) Na2SO3 (aq) + BaCl2 (aq) → BaSO3(s) + 2NaCl (aq)
(b) Double displacement reaction
(c) Addition of HCl dissolves the white precipitate of BaSO3 and form soluble BaCl2.
BaSO3 (s) + 2HCl (aq) → BaCl2 (aq) + H2O (l) + SO2 (g)
Question. 44 You are provided with two containers made up of copper and aluminium. You are also provided with solutions of dilute HCl, dilute HNO3, ZnCl2 and H2O. In which of the containers these solutions can be kept?
Answer.
(i) Reactions of copper with
(a) Dilute HCI: Copper exhibits no reaction with HCl so it can store in copper container.
(b) Dilute HNO3: With dilute nitric acid, copper metal forms copper nitrate with nitric oxide and water so dilute nitric acid cannot store in copper container.
Cu(s) + 8HNO3 (dil) → 3Cu(NO3)2 (aq) + 2NO (g) + 4H2O(l)
(c) ZnCl2:Since Cu metal is less reactive than Zn so it cannot displace Zn from its compounds and there will be no reaction. Hence zinc chloride can store in copper container.
(d) H2O: There is no reaction between water and copper metal at room temperature so water can store in copper container.
(ii) Reactions of aluminium with
(a) Dilute HCI: Aluminium reacts with Al reacts with dilute HCI and form aluminium chloride with hydrogen gas so it cannot be store in aluminium container.
2Al + 6HCl → 2AlCl3 + 3H2
(b) Dilute HNO3: Nitric acid is an oxidizing agent and in the presence of it, aluminium metal forms a protective layer of oxide so it will not react further. Hence dilute nitric acid can store in aluminium container.
(c) ZnCl2: Aluminium readily reacts with zinc chloride and forms aluminium chloride with zinc metal.
2Al + 3ZnCl2 → 2AlCl3 + 3Zn
Hence it cannot store in zinc container.
(d) H2O:At room temperature, there will be no reaction between aluminium metal and water so it can store in aluminium container.