CBSE Class 10 Chemistry Chemical Reactions And Equations Worksheet Set B

MULTIPLE CHOICE QUESTIONS:

Question. Some crystals of copper sulphate were dissolved in water. The color of the solution obtained would be:
(a) Green
(b) Red
(c) Blue
(d) Brown
Answer. C

Question. When Zinc pieces are added to dilute HCl taken in a test tube, then:
(a) No change takes place
(b) The colour of the solution becomes yellow.
(c) A pungent smelling gas gets liberated
(d) Small bubbles of H₂ gas appear on the surface of zinc pieces
Answer. D

Question. PbS reacts with ozone (O₃) and forms PbSO₄. As per the balanced equation, molecules of ozone required for every one molecule of PbS is/are:
(a) 4
(b) 3
(c) 2
(d) 1
Answer. A

Question. Chemically rust is:
(a) Hydrated ferrous oxide
(b) Hydrated ferric oxide
(c) Only ferric oxide
(d) None of these
Answer. B

Question. In the reaction:
PbO + C→ Pb + CO
(a) PbO is oxidised
(b) C acts as an oxidising agent
(c) Carbon acts as a reduction agent
(d) Reaction does not represent redox reaction.
Answer. C

Question. A substance which oxidizes itself and reduces other is known as:
(a) Oxidising agent
(b) Reducing agent
(c) Both (a) and (b)
(d) None of these.
Answer. B

Question. The reaction between lead nitrate and potassium iodide present in aqueous solution is an example of
(a) Decomposition Reaction
(b) Displacement Reaction
(c) Double Displacement Reaction
(d) Neutralisation Reaction
Answer. C

Question. What happens when dilute hydrochloric acid is added to iron filling? Tick the correct answer
(a) Hydrogen gas and iron chloride are produced.
(b) Chlorine gas and iron hydroxide are produced
(c) No reaction takes place
(d) Iron salt and water are produced
Answer. A

Question. A student adds lead and silver to two different test tubes containing an equal amount of Copper Sulphate solution. The student observes that the color of the solution in the test tube with lead changes. What explains the change in the color of the solution?
(a) A displacement reaction takes place as lead replaces copper from the solution.
(b) A combination reaction takes place as lead combines with sulphate in the solution.
(c) Decomposition reaction takes place as copper dissociates from sulphate in the solution.
(d) A double displacement reaction takes place as copper dissociates from sulphate and lead combines with sulphate in the solution.
Answer. B

Question. In an electrolytic cell where electrolysis is carried, cathode has:
(a) Positive change
(b) Negative charge
(c) Connected to negative terminal of the battery
(d) None of these is correct.
Answer. A

Question. In the decomposition of lead (II) nitrate to give lead (II) oxide, nitrogen dioxide and oxygen gas, the coefficient of nitrogen dioxide (in the balanced equation) is
(a) 1
(b) 2
(c) 3
(d) 4
Answer. D

Question. Which of the following is not a balanced equation?
(a) Fe + Cl₂ →FeCl₃
(b) Mg + CuSO₄ → MgSO₄ +Cu
(c) NaOH + HCl → NaCl + H₂O
(d) Zn + S → ZnS
Answer. A

Question. Dissolving sugar is an example of:
(a) Physical change
(b) Chemical change
(c) Redox reaction
(d) None of these
Answer. A

Question. We store silver chloride in dark colored bottles because it is
(a) A white solid
(b) Undergoes redox reaction
(c) To avoid action by sunlight
(d) None of the above.
Answer. C

Question. The reaction H₂ + Cl₂ → 2 HCl represents:
(a) oxidation
(b) reduction
(c) decomposition
(d) combination
Answer. D

Question. Copper displaces which of the following metals from its salt solution:
(a) ZnSO₄
(b) FeSO₄
(c) AgNO₃
(d) NiSO₄
Answer. C

Question. Which of the following statements about the given reaction are correct?
3Fe (s) + 4H₂O (g) → Fe3O₄ (s) + 4 H₂ (g)
(i) Iron metal is getting oxidised
(ii) Water is getting reduced
(iii) Water is acting as reducing agent
(iv) Water is acting as oxidising agent
(a) (i), (ii) and (iii)
(b) (ii) and (iv)
(c) (i), (ii) and (iv)
(d) (ii) and (iv)
Answer. C

Question. 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

Question. A dilute ferrous sulphate solution was gradu¬ally added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disap¬pears.Which of the following is the correct explanation for the observation?
(a) KMnO₄ is an oxidising agent, it oxidises FeSO₄.
(b) FeSO₄ acts as an oxidising agent and oxidises KMNO₄.
(c) The colour disappears due to dilution; no reaction is involved.
(d) KMnO₄ is an unstable compound and de-composes in presence of FeSO₄. to a colourless compound
Answer. A

Question. In an electric cell where electrolysis is carried out, anode has:
(a) Positive charge
(b) Negative charge
(c) Connected to negative terminal of the battery
(d) None of these is correct
Answer. A

ASSERTION- REASON QUESTIONS :

DIRECTION: Each of these questions contains an Assertion followed by Reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.
(a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
(c) If Assertion is correct but Reason is incorrect.
(d) If Assertion is incorrect but Reason is correct

Question. Assertion: Stannous chloride is a powerful oxidising agent which oxidises mercuric chloride to mercury.
Reason: Stannous chloride gives grey precipitate with mercuric chloride, but stannic chloride does not do so.
Answer. C

Question. Assertion: Corrosion of iron is commonly known as rusting.
Reason: Corrosion of iron occurs in presence of water and air.
Answer. B

Question. Assertion: In a reaction.
Zn(s) + CuSO₄ (aq) ZnSO₄ (aq) + Cu(s) Zn is a reductant but itself get oxidized.
Reason: In a redox reaction, oxidant is reduced by accepting electrons and reductant is oxidized by losing electrons.
Answer. A

Question. Assertion: A reducing agent is a substance which can either accept electron.
Reason: A substance which helps in oxidation is known as reducing agent.
Answer. D

Question. Assertion: The balancing of chemical equations is based on law of conservation of mass.
Reason: Total mass of reactants is equal to total mass of products.
Answer. A

VERY SHORT ANSWER TYPE QUESTIONS:

Question. What is a redox reaction?
Answer. A redox reaction can be defined as a chemical reaction in which electrons are transferred between two reactants participating in it.

Question. Why is photosynthesis considered as an endothermic reaction?
Answer. Photosynthesis is considered an endothermic reaction, because during the process of photosynthesis, energy from the sun or sunlight is being absorbed.

Question. In electrolysis of water, why is the volume of gas collected over one electrode double that of the other electrode?
Answer. The amount of H is double than that of O. The two electrodes collect H₂ and O₂ separately, therefore, the volume of gas collected in one electrode is double the volume of gas collected in the other electrode.

Question. What happens when water is added to solid calcium oxide taken in a container? Write a chemical formula for the same.
Answer. When calcium oxide is added to water it forms calcium hydroxide Called slaked lime.
CaO +H₂O →Ca(OH)₂ The reaction between water and CaO is an exothermic reaction.

Question. Name the compound used for testing CO₂ gas.
Answer. Calcium hydroxide solution (freshly prepared), also called lime water, is used to test CO2 gas.

SHORT ANSWER TYPE QUESTIONS:

Question. Identify the type of chemical reaction
(i) A → B+C
(ii) AB+CD → AD+CB
Answer.  (i) Decomposition reaction
(ii) Double displacement reaction

Question. Why does not silver evolve hydrogen on reacting with dil. H₂SO₄?
Answer. Silver do not evolve hydrogen on reacting with dil. H₂SO₄ as silver is less reactive metal than hydrogen.

Question. Why a combustion reaction an oxidation reaction?
Answer. Combustion reaction because it is always carried out in the presence of air or oxygen for
e.g. CH₄ (g) + 2O₂ (g) → Co₂ (g) +2H₂O (l)

Question. A student took 2-3 g of a substance X in a glass beaker & poured water over it slowly. He observed bubbles along with hissing noise. The beaker becomes quite hot. Identify X. What type of reaction is it?
Answer. X = Calcium oxide (Quick lime), Combination reaction.

Question. Why should a magnesium ribbon be cleaned before burning in air?
Answer. Magnesium ribbon is cleaned before burning to remove the protective layer of basic magnesium Oxide from the surface of magnesium ribbon.

LONG ANSWER TYPE QUESTIONS

Question. A student dropped few pieces of marble in dilute hydrochloric acid contained in a test tube. The evolved gas was then passed through lime water. What change would be observed in lime water? Write balanced chemical equation for both the change observed?
Answer. When marble (CaCO₃ )reacts with dil. HCl, CO₂ gas evolved
CaCO₃ (s) +2HCl (aq)→ CaCl₂ (aq) + H₂O (l) + CO₂ (g)
When this gas is evolved and is passed through lime water, becomes milky due to the formation of insoluble Calcium carbonate.
Ca (OH) ₂ + CO₂ (g)→CaCO₃ (s) +H₂O (l)
But when milkiness disappears i.e. when CO₂ gas is passed in excess through CaCO₃ (s)
CaCO₃ (s) + CO₂ (g) +H₂O (l)→Ca (HCO₃)₂ (aq.)

Question. An aqueous solution of metal nitrate P reacts with sodium bromide solution to form Yellow ppt of compound Q which is used in photography. Q on exposure to sunlight undergoes decomposition reaction to form metal present in P along with reddish brown gas. Identify P &Q. Write the chemical reaction & type of chemical reaction and define it?
Answer. P = Ag NO₃ Q= AgBr 2AgBr → 2Ag+Br₂
Photochemical decomposition.
The decomposition reaction that occurs in the presence of light is photochemical reaction.

Question. What happens to lime water when CO₂ gas is bubbled through it in excess?
Answer. When CO₂ gas is bubbled through lime water in excess then initially it becomes milky but after some time its milkiness disappears. This is because initially calcium carbonate is formed which causes the lime water to turn milky and when further CO₂ is passed calcium bicarbonate is formed which turns the solution colorless.

Question. A substance X used for coating iron articles is added to a blue solution of a reddish-brown metal Y,the colour of the solution gets discharged. Identify X and Y & also the type of reaction.
Answer. Here, a substance X used for coating iron articles is added to a blue solution of a reddish-brown metal Y , the colour of the solution gets discharged. Therefore, X is Iron ( Fe ) Y is Copper ( Cu ).
Also, it is a type of a displacement reaction.

Question. A compound ‘X’ is used for drinking, has pH =7. Its acidified solution undergoes decomposition in presence of electricity to produce gases ‘Y ’and ‘Z ’. The volume of Y is double than Z. Y is highly combustible whereas Z is supporter of combustion. Identify X, Y & Z and write the chemical reactions involved.
Answer. In the given situation, X= H₂O, 2Y =H₂ and Z=O₂.
The chemical reaction involved is:
2H₂O → 2H₂+O₂

Question. MnO₂ + 4HCl → MnCl₂ + H₂O + Cl₂ The oxidising agent is
(a) MnO₂
(b) HCl
(c) MnCl₂
(d) Ag + Zn(NO₃)₃

Answer : A

Question. Which of the following are exothermic processes?
(i) Reaction of water with quick lime
(ii) Dilution of an acid
(iii) Evaporation of water
(iv) Sublimation of camphor (crystals)
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (ii) and (iv)

Answer : A

Question. Burning Magnesium ribbon is brought in the gas jar of carbon dioxide. Which of the following is correct ?
(i) It keeps on burning
(ii) It gets extinguished
(iii) Although CO₂ is non-supporter of combustion but burning magnesium breaks CO2 into carbon and oxygen, oxygen helps in burning.
(iv) Carbon dioxide is supporter of combustion.
(a) (i) and (iv)
(b) (i) and (iii)
(c) (i) and (ii)
(d) (iii) and (iv)

Answer : B

Question. The process of reduction involves
(a) addition of oxygen
(b) addition of hydrogen
(c) removal of oxygen
(d) removal of hydrogen

Answer: B

Question. Which among the following is (are) double displacement reactions ? 
(i) Pb + CuCl₂ → PbCl₂ + Cu
(ii) Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl
(iii) C + O₂ → CO₂
(iv) CH₄ + 2O₂ → CO₂ + 2H₂O
(a) (i) and (iv)
(b) (ii) only
(c) (i) and (ii)
(d) (iii) and (iv)

Answer: B

Question. 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 solution 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?
(i) In beakers A and B, exothermic process has occurred.
(ii) In beakers A and B, endothermic process has occuBftd.
(iii) In beaker C exothermic process has occurred.
(iv) In beaker C endothermic process has occurred.
(a) (i) only
(b) (ii) only
(c) (i) and (iv)
(d) (iv), (ii) and (iii)

Answer : C

Question. When S0₂ gas is passed through saturated solution of H2S, which of the following reaction occurs?
(a) SO₂ + 2H₂S → 2H₂0 + 3S
(b) SO₂ + 2H₂S → H₂0 + 3S
(c)SO₂ + H₂S → H₂O + S
(d) SO₂ + H₂O → SO₃ + H₂

Answer : A

Question. 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) (iv) only

Answer : A

Question. The brown gas evolved on heating of copper nitrate is
(a) O₂
(b) NO₂
(c) N₂
(d) NO

Answer : B

Question. Select the oxidising agent for the following reaction:
H₂S + I₂ > 2HI + S
(a) I₂
(b) H₂S
(C) HI
(d) S

Answer : A

Question. 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) (i) only
(b) (ii) only
(c) (iv) only
(d) (ii) and (iv)

Answer : D

Question. When Ag is exposed to air it gets a black coating of
(a) AgNO₃
(b) Ag₂S
(c) Ag₂O
(d) Ag₂CO₃

Answer : B

Question. A substance ‘X’ is used in white-washing and is obtained by heating limestone in the absence of air. Identify ‘X’.
(a) CaOCl₂
(b) Ca (OH)₂
(c) CaO
(d) CaCO₃

Answer: C

Question. Which of the following gases can be used for storage
(a) Carbon dioxide or Oxygen
(b) Nitrogen or Oxygen
(c) Carbon dioxide or Helium
(d) Helium or Nitrogen

Answer : D

Question. Which of the following is an endothermic process?
(a) Dilution of sulphuric acid
(b) Sublimation of dry ice
(c) Condensation of water vapours
(d) Respiration in human beings

Answer : B

Question. The colour of iodine is
(a) green
(b) purple
(c) brown
(d) pink

Answer : B

Question. 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)
(&) Lead acetate
(c) Ammonium nitrate
(d) Potassium sulphate

Answer : B

Question. Which of the following is (are) an endothermic process(es) ? 
(z) Dilution of sulphuric acid
(ii) Sublimation of dry ice
(iii) Condensation of water vapours
(iv) Evaporation of water
(a) (i) and (iii)
(b) (ii) only
(c) (iii) only
(d) (ii) and (iv)

Answer : D

Question. What type of chemical reactions take place when electricity is passed through water?
(a) Displacement
(b) Combination
(c) Decomposition
(d) Double displacement

Answer : C

Question. The formula of Ammonium phosphate is
(a) NH₄PO₄
(b) (NH₄)2PO₄
(c) (NH₄)₃PO₄
(d) (NH4)₃(PO₄)₂

Answer : C

Assertion and Reason Type MCQs : 

Following questions consists of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
A. Both assertionand reason are true, and reason is the correct explanation of assertion.
B. Both assertion and reason are true, but reason is not the correct explanation of assertion.
C. Assertion is true but reason is false.
D. Assertion is false and reason is true.

Question. Assertion(A): The colour of salts does not depend on water of crystallisation.
Reason(R): Ferrous Sulphate crystals are blue in colour because of the seven water molecules of crystallisation.

Answer: D

Question. Assertion(A): Addition of oxygen is oxidation.
Reason(R): Removal of oxygen is reduction.

Answer: B

Question. Assertion(A): Silver Bromide is used in black and white photography.
Reason(R): Silver Bromide decomposes in the presence of sunlight.

Answer: B

Question. Assertion(A): Silver Chloride turns grey in sunlight.
Reason(R): This is an example of thermal decomposition.

Answer: C

Question. Assertion(A): Reaction between Barium Hydroxide and Ammonium Chloride makes the test tube cool to touch.
Reason(R): It is an example of endothermic reaction.

Answer: A

Question. Assertion(A): The surface of copper powder becomes black on heating.
Reason: Black colour copper oxide is formed.

Answer: A

Question. Assertion(A): Brown fumes are obtained from the thermal decomposition of Lead Nitrate.
Reason(R): Nitrogen dioxide gas is released which is brown in colour.

Answer: A

Question. Assertion(A): Decomposition of Calcium Carbonate is a type of chemical reaction.
Reason(R): Chemical reactions involve the breaking and making of bonds to produce new substances.

Answer: A

Question. Assertion(A): Fatty foods taste the same even after long periods of exposure to air.
Reason(R): We should store oily foods in air tight containers.

Answer: D

CASE BASED MCQs

I. Clean a magnesium ribbon about 2 cm long by rubbing it with sandpaper. Hold it with a pair of tongs. Burn it using a spirit lamp or burner and collect the ash so formed in a watch-glass. 

Question. What is the chemical name of the powder obtained in the activity?
A. magnesium carbonate
B. magnesium oxide
C. magnesium sulphide
D. magnesium chloride

Answer: B

Question. Which compound is formed when the powder obtained reacts with water?
A. Magnesium sulphate
B. Magnesium oxide
C. Magnesium carbonate
D. Magnesium hydroxide

Answer: D

Question. Magnesium ribbon is rubbed before burning because it has a coating of
A. basic magnesium carbonate
B. basic magnesium oxide
C. basic magnesium sulphide
D. basic magnesium chloride

Answer: A

Question. What is the colour of magnesium ribbon?
A. White
B. Black
C. Grey
D. Yellow

Answer: C

II. Take a plastic mug, drill two holes at its base and insert carbon electrodes. Connect these electrodes to a 6 volt battery. Fill the mug with water such that the electrodes are
immersed. Add a few drops of dilute sulphuric acid to the water. Take two test tubes 

filled with water and invert them over the two carbon electrodes. Switch on the current and leave the apparatus undisturbed for some time.

Question. Where is hydrogen gas collected?
A. Anode
B. Cathode
C. At both electrodes
D. Hydrogen gas is not evolved in this activity

Answer: B

Question. Which of the following is an endothermic process?
A. Dilution of sulphuric acid
B. Condensation of water vapours
C. Respiration in human beings
D. Electrolysis

Answer: D

Question. What is the ratio in which hydrogen and oxygen are present in water by volume?
A. 1:2
B. 1:1
C. 2:1
D. 1:8

Answer: C

Question. Which electrodes are used in this activity?
A. Graphite
B. Diamond
C. Copper
D. Coke

Answer: A

III. Take about 2 g ferrous sulphate crystals in a dry boiling tube. Heat the boiling tube over the flame of a burner or spirit lamp. In this reaction you can observe that a single reactant breaks down to give simpler products. This is a decomposition reaction.
Ferrous sulphate crystals (FeSO₄, 7H₂O) lose water when heated and the colour of the crystals changes. It then decomposes to ferric oxide (Fe₂O₃), sulphur dioxide (SO₂) and sulphur trioxide (SO₃). Ferric oxide is a solid, while SO2 and SO3 are gases. 

Question. What compound is formed when sulphur dioxide is passed through water?
A. Sulphuric acid
C. Hydrogen Sulphide
B. Sulphurous acid
D. Sulphur trioxide

Answer: C

Question. What can we observe in this activity?
A. Water vapor is evolved
B. Change in colour
C. Smell of burning sulphur
D. All of the above.

Answer: D

Question. What is the colour of iron oxide?
A. Brown
C. Yellow
B. Grey
D. White

Answer: A

Question : Why decomposition reactions are called the opposite of combination reactions? Write equations for these reactions.
Answer :  A decomposition reaction may be defined as the reaction in which a single substance decomposes or splits into two or more substances under suitable conditions.
For example,

Question :   Identify the type of reaction in the following examples :
(i) Na₂SO₄(aq) + BaCl₂(aq) ———-> BaSO₄(s) + 2NaCl(aq)
(ii) Fe(s) + CuSO₄(aq) ———-> FeSO₄(aq) + Cu(s)
(iii) 2H₂(g) + O₂(g) ———> 2H₂O(l)
Answer :
(i) It is an example of double displacement reaction.
(ii) It is an example of displacement reaction.
(iii) It is an example of combination reaction.

Question : When Hydrogen gas is passed over heated copper (II) oxide, copper and steam are formed. Write the balanced chemical equation with physical states for this reaction. State what kind of chemical reaction is this?
Answer :

This is a Redox reaction.

Question : Define a combination reaction. Give one example of a combination reaction which is also exothermic.
Answer :   A combination reaction is said to have occurred when two or more than two substances combine to form a single substance.

Question : Name and state the law which is kept in mind while we balance a chemical equation.
Answer :   Law of conservation of mass. Mass can neither be created nor be destroyed during a chemical reaction.

Question :   Which of the following statements about the given reaction are correct?
3Fe (s) + 4H₂O (g) → Fe₃O₄ (s) + 4 H₂ (g)
(i) Iron metal is getting oxidized
(ii) Water is getting reduced
(iii) Water is acting as reducing agent
(iv) Water is acting as oxidizing agent
(a) (i), (ii) and (iii)
(b) (ii) and (iv)
(c) (i), (ii) and (iv)
(d) (ii) and (iv)
Answer: C

Question : Oxidation is a process which involves
(i) addition of oxygen
(ii) addition of hydrogen
(iii) removal of oxygen
(iv) removal of hydrogen
a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (ii) and (iv)
Answer : C

Question :
(a) Why cannot a chemical change be normally reversed?
(b) Why is it always essential to balance a chemical equation?
(c) Why do diamond and graphite, the two allotropic forms of carbon evolve different amounts of heats on combustion?
(d) Can rusting of iron take place in distilled water?
Answer :
(a) In a chemical change, the products are quite different from the reactants. Therefore, it cannot be normally reversed.
(b) A chemical equation has to be balanced to meet the requirement of the law of conservation of mass. According to the law, the total mass of the reacting species taking part in the reaction is the same as that of the products formed. Since there is a direct relationship between the mass of the different species and their number, it is always essential to balance a chemical equation.
(c) Because they differ in the arrangement of carbon atoms present and have different shapes. The attractive forces among the atoms in the two cases are not same. That is why they evolve different amount of heat.
C(diamond) + O₂(g) ———–> CO₂(g) + 393.5 kj
C(graphite) + O₂(g) ———–> CO₂(g) + 395.4 kj
Please note that diamond and graphite are the two allotropic forms of carbon.
(d) No, rusting of iron cannot take place in distilled water because it neither contains dissolved oxygen nor carbon dioxide. Both are essential for the rusting of iron.

Question :   A silvery white metal X is in the form of ribbons. Upon ignition, it burns with a dazzling white flame to form white powder Y. When water is added to the powder Y, it partially dissolves to form a substance Z which is used as an antacid.
(a) What is metal X?
(b) Name the white powder Y.
(c) What is the substance Z ?
(d) Write the chemical reactions that are taking place.
Answer :
(a) The metal is X is Mg.
(b) The white powder Y is MgO.
(c) White powder Y dissolves partially in water to form substance Z. It is Mg (OH), and is used as an antacid.
(d) The chemical reactions that are taking place are :