CBSE Class 10 Chemistry Chemical Reactions And Equations Worksheet Set A

Question. In the balanced equation -
aHgS+bHCl + cHNO₃ → dH₂HgCl₄ + eNO + fS + gH₂O
The values of b, c, e, and g are respectively -
(A) 2, 2, 4, 12
(B) 6, 1, 1, 2
(C) 12,2, 2, 4
(D) both (B) and (C)
Answer. D

Question. In the reaction FeSO₄ + x → Na₂SO₄ + Fe(OH)₂ , x is -
(A) Na₂SO₄
(B) H₂SO₄
(C) NaOH
(D) none of these
Answer. C

Question. In the reaction the possible state of Ca(OH)₂ is -
(A) liquid.
(B) aqueous.
(C) gaseous.
(D) solid.
Answer. B

Question. The rate of reaction remains same, when -
(A) temperature of the reaction changes.
(C) both (A) and (B) are correct
(B) catalyst is added to reaction mixture.
(D) none of these is correct
Answer. D

Question. aK₂Cr₂O₇ + bKCl + cH₂SO₄ → xCrO₂Cl₂ + y KHSO₄ + zH₂O
The above equation balances when
(A) a = 2, b = 4, c = 6 and x = 2, y = 6 , z = 3
(B) a = 4, b = 2, c = 6 and x = 6, y = 2, z = 3
(C) a = 6, b = 4, c = 6 and x = 6, y = 3, z = 2
(D) a = 1, b = 4, c = 6 and x = 2, y = 6, z = 3
Answer. D

Question. In the reaction Mg + Cl₂ → MgCl₂
Chlorine may be regarded as -
(A) an oxidising agent
(C) a catalyst
(B) a reducing agent
(D) providing an inert medium
Answer. A

Question. The antioxidant which is used to prevent rancidity in foods is
(A) butylated hydroxyl anisole.
(B) sodium hydroxide.
(C) sodium carbonate.
(D) methylated hydroxyl anisole
Answer. A

Question. The colour of the chemical that changes when it is left open in sunlight is -
(A) FeSO₄ (s).
(B) Pb(NO₃)₂ (s)
(C) AgCl (s).
(D) BaCl₂ (aq)
Answer. C

Question. Sun produces heat and light by -
(A) combustion.
(B) inflammation.
(C) nuclear reactions.
(D) photochemical reactions.
Answer. C

Question. Heating of calcium carbonate to give calcium oxide and carbon dioxide is -
(A) An oxidation process
(B) A reduction process
(C) Disproportionation
(D) Decomposition
Answer. D

Question. Which of the following statement(s) is/are correct ?
(A) Many compounds can be used as oxidizing as well as reducing agent .
(B) We need equal moles and equal volumes of strong monobasic acid and strong monoacidic base to completely neutralize themselves.
(C) The quantity of a catalyst does not change at the end of a chemical reaction .
(D) All of these are correct
Answer. D

Question. The elements undergoing reduction and oxidation during the reaction,
(NH₄)₂Cr₂O₇ → N₂ + Cr₂O₃ + 4H₂O are respectively
(A) N and Cr
(B) Cr and N
(C) N and O
(D) Cr and O
Answer. B

Question. The decomposition of KCIO₃ to KCI and O₂ on heating is an example of:
(A) Intermolecular redox change
(B) Intramolecular redox change
(C) Disproportionation or auto redox change
(D) None of the above
Answer. B

Question. Which of the following can act as oxidant ?
(A) H₂O₂
(B) H₂S
(C) NH₃
(D) None of these
Answer. A

Question. Conversion of PbSO₄ to PbS is -
(A) reduction of S
(B) oxidation of S
(C) dissociation
(D) none of these
Answer. A

Question. Which of the following is redox reaction ?
(A) NaOH + HCl → NaCl + H₂O
(B) AgNO₃ + KI → AgI + KNO₃
(C) BaO₂ + H₂SO₄ → BaSO₄ + H₂O₂
(D) SnCI₂ + HgCI₂ → SnCI₄ + Hg
Answer. D

Question. In a conjugate pair of reductant and oxidant, the reductant has :
(A) Lower ox. no.
(B) Higher ox. no.
(C) Same ox. no.
(D) Either of these
Answer. A

Question. Oxidation is process which involves:
(A) De-electronation
(B) Electronation
(C) Addition of hydrogen
(D) Addition of metal
Answer. A

Question. Oxidants are substances which :
(A) Show a decrease in their oxidation number during a change
(B) Gain electrons during a change
(C) Oxidise others and reduce themselves
(D) All of the above
Answer. D

Question. If an iron rod is dipped in CuSO₄ solution :
(A) Blue colour if the solution turns red
(B) Brown layer is deposited on iron rod
(C) No change occurs in the colour of the solution
(D) None of the above
Answer. B

Question. Which of the following is a redox reaction ?
(A) CaCO₃ → CaO + CO₂
(B) H₂ + Cl₂ → 2HCl
(C) CaO + 2HCl → CaCl₂ + H₂O
(D) NaOH + HCl → NaCl + H₂O
Answer. B

Question. Which of the following statement about the following reaction is correct
ZnO + CO → Zn + CO₂
(A) ZnO is being oxidised
(B) CO is being reduced
(C) CO2 is being oxidised
(D) ZnO is being reduced
Answer. D

Question. Calorific value of a fuel may be defined as -
(A) The amount of heat produced when 1000 kg of a fuel is completely burnt.
(B) The amount of heat produced when 1 g of fuel is incompletely burnt.
(C) The amount of heat produced when 10 g of a fuel is completely burnt.
(D) The amount of heat produced in kilojoules when unit mass of a fuel is completely burnt.
Answer. D

Question. Which of the following fuels has the highest calorific value ?
(A) Petrol
(B) Hydrogen
(C) LPG
(D) Natural gas
Answer. B

Question. In which zone of a candle flame does complete combustion take place ?
(A) Inner
(B) Outer
(C) Middle
(D) All three zones
Answer. B

Question. The zone of no combustion is -
(A) the middle zone
(B) outermost zone
(C) the base of the flame
(D) innermost zone.
Answer. D

Question. The colour of the flame in luminous zone is -
(A) blue.
(B) red.
(C) yellow.
(D) black.
Answer. C

Question. The non-combustible substance among the following is -
(A) coal.
(B) glass.
(C) wood.
(D) paper.
Answer. B

Question. Combustion is a -
(A) physical process
(B) chemical process
(C) biological process
(D) mechanical process
Answer. B

Question. A circular blackish ring on the glass plate kept over the candle flame indicates-
(A) complete combustion.
(B) dark zone of the flame.
(C) non-luminous zone.
(D) luminous zone
Answer. D

Question. Combustion is a process involving -
(A) oxidation
(B) reduction
(C) liberation of heat
(D) all(A),(B) & (C)
Answer. D

CASE STUDY BASED QUESTIONS:

Question. Read the following and answer the questions :

A student was asked to investigate what happens when a piece of shiny magnesium ribbon is added to copper sulphate solution. The apparatus was set up as shown below. The mass was recorded at the start and again after one hour.

Question. Complete the equation:
Mg + CuSO₄ →--------- + ---------
(a) MgSO₄ + Cu
(c) MgS + Cu₂O
(b) MgO + Cu
(d) Mg SO₃ + Cu₂O
Answer. A

Question. Choose from below the name given to this type of reaction:
(a) Combustion
(b) Displacement
(c) Corrosion
(d) Electrolysis
Answer. B

Question. Balance the following symbol equation that represents the displacement reaction that takes place between zinc and silver nitrate solution.
Zn + AgNO₃ → Zn(NO₃)₂ + Ag
(a) Zn + 2AgNO₃ → Zn(NO₃)₂ + 2Ag
(b) Zn + 3AgNO₃ → Zn(NO₃)₂ + 3Ag
(c) Zn + 2AgNO₃ → Zn(NO₃)₂ + Ag
(d) 2 Zn + AgNO₃ → Zn(NO₃)₂ + Ag
Answer. A

Question. The experiment was repeated using sodium sulphate solution instead of copper sulphate solution.
No reaction took place. Put the metals copper, magnesium and sodium in order of reactivity.
(a) I. Sodium II Copper III Magnesium
(b) I Magnesium II Copper III Sodium
(c) I. Copper II. Magnesium III. Sodium
(d) I. Sodium II. Magnesium III. Copper
Answer. D

Question. What will be the mass of the beaker and content after 1 hour?
(a.) More than 80.6 g
(b) Equal to 80.6 g
(c) Less than 80.6 g
(d) None of the above
Answer. B

Read the following and answer the questions :

Called the reducing agent; when the reaction occurs, it reduces the other species. In other words, what is oxidized is the reducing agent and what is reduced is the oxidizing agent.
A good example of a redox reaction is the thermite reaction, in which iron atoms in ferric oxide
lose (or give up) O atoms to Al atoms, producing Al₂O₃.
Fe₂O₃ (s) +2Al (s)→Al₂O₃ (s)+2Fe (l)
Redox reactions can occur relatively slowly, as in the formation of rust, or much morerapidly, as in the case of burning fuel. There are simple redox processes, such as theoxidation

Question. Which of the following is correct code for X and Y in the following reaction ?

(i) x=oxidation reaction, y=reduction reaction
(ii) x=gain of two electrons, y=loss of two electrons,
(iii) x=reduction reaction, y=oxidation reaction
(iv) x=loss of two electrons, y=gain of two electrons
(a) (i) and (ii)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (iii) and (iv)
Answer. B

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

Question. ‘Thermite is a pyrotechnic composition of metal powder, which serves as fuel, and metal oxide.
When ignited by heat, thermite undergoes a reaction between iron and Aluminum Oxide and is used in the wielding of railway tracks. The type of reaction is called:
a) Reduction
c) Redox
b) Oxidation
d) Decomposition
Answer. C

Question. “Redox reactions can occur relatively slowly, as in the formation of rust, or much more rapidly, as in the case of burning fuel” Rusting and combustion are quite different. Which of the following lines is not the correct explanation for this?
(a) Rusting occurs at the surface of iron to form a layer of rust.
(b) Rusting gives out lots of heat and light.
(c) Rusting is an example of slow oxidation.
(d) It can be hampered by applying paint.
Answer. B

Question. Reduction can be defined as:
(a) Gain of electrons
(b) Gain of Oxygen
(c) Loss of Hydrogen
(d) Loss of electrons
Answer. A

Read the following and answer the questions :

Oxidation is the process of gaining of oxygen, or losing of hydrogen. Reduction is the process of losing of oxygen or gaining of hydrogen. The substance which undergoes oxidation is the reducing agent while the substance which undergoes reduction is known as the oxidising agent. Oxidation and reduction always take place together and these types of reactions are known as redox reactions. Some of the examples of redox reactions are given below:

Question. Give two examples of oxidation reaction from your everyday life.
Answer. corrosion & rancidity

Question. Write the oxidising agent in the reaction III and VI.
Answer. CuSO₄ in (III) & CuO in(VI)

Question. Which of the following is an oxidising agent?
(a) LiAlH₄
(b) Alkaline KMnO₄
(c) Acidified K2Cr₂O₇
(d) Both (b) and (c)
Answer. D

Question. Out of oxidation and reduction, which reaction takes place at anode?
Answer. oxidation

Question. Which substance undergoes reduction?
Answer. oxidizing agent

Read the following and answer the questions :

A chemical reaction is a representation of chemical change in terms of symbols and formulae of reactants and products. There are various types of chemical reactions like combination,
decomposition, displacement, double displacement, oxidation and reduction reactions. Reactions in which heat is released along with the formation of products are called exothermic chemical reactions. All combustion reactions are exothermic reactions.

Question. The chemical reaction in which a single substance breaks down into two or more simpler substances upon heating is known as
(a) thermal decomposition reaction
(b) photo decomposition reaction
(c) electric decomposition reaction
(d) both (a) and (c)
Answer. A

Question. The massive force that pushes the rocket forward through space is generated due to the
(a) combination reaction
(b) decomposition reaction
(c) displacement reaction
(d) double displacement reaction
Answer. B

Question. A white salt on heating decomposes to give brown fumes and yellow residue is left behind. The yellow residue left is of
(a) lead nitrate
(b) nitrogen oxide
(c) lead oxide
(d) oxygen gas
Answer. C

Question. Which of the following reactions represents a combination reaction?
(a) CaO (s) + H₂O (l) → Ca(OH)₂ (aq)
(b) CaCO₃ (s) → CaO (s) + CO₂(g)
(c) Zn(s) + CuSO₄ (aq) → ZnSO₄ (aq) + Cu(s)
(d) 2FeSO₄(s) → Fe₂O₃ (s) +SO₂(g) + SO₃(g)
Answer. A

Question. Complete the following statements by choosing correct type of reaction for X and Y.
Statement 1: The heating of lead nitrate is an example of ‘X’ reaction.
Statement 2: The burning of magnesium is an example of ‘Y’ reaction.
(a) X- Combination, Y- Decomposition
(b) X- Decomposition, Y-Combination
(c) X- Combination, Y-Displacement
(d) X- Displacement, Y-Decomposition
Answer. B

Read the following and answer the questions :

Chemical equation is a method of representing a chemical reaction with the help of symbols and formulae of the substances involved in it. In a chemical equation, the substances which combine or react are called reactants and new substances produced are called products. A chemical equation is a short hand method of representing a chemical reaction. A balanced chemical equation has equal number of atoms of different elements in the reactants and products side. An unbalanced chemical equation has unequal number of atoms of one or more elements in reactants and products. Formulae of elements and compounds are not changed to balance an equation.

Question.Consider the following reaction:
pMg₃N₂ + qH₂O ⇾ rMg(OH)₂ + sNH₃
When the equation is balanced, the coefficients p, q, r, s respectively is
(a) 1,3,3,2
(c) 1,6,3,2
(b) 1,2,3,2
(d) 2,3,6, 2
Answer. B

Question. Which of the following information is not conveyed by a balanced chemical equation?
(a) Physical states of reactants and products
(b) Symbols and formulae of all the substances involved in a particular reaction
(c) Number of atoms/molecules of the reactants and products formed
(d) Whether a particular reaction is actually feasible or not
Answer. D

Question. The balancing of chemical equations is in accordance with
(a) Law of combining volumes
(b) Law of constant proportions
(c) Law of conservation of mass
(d) Both (b) and (c)
Answer. C

Question. Which of the following chemical equations is an unbalanced one?
(a) 2NaHCO₃ ⟶ Na₂CO₃+H₂O+CO₂
(b) 2C₄H₁₀+12O₂ ⟶ 8CO₂+10H₂O
(c) 2Al+6H₂O ⟶ 2Al(OH)₃+3H₂
(d) 4NH₃+5O₂ ⟶ 4NO+6H₂O
Answer. B

Question. Which of the following statements is/are correct?
(a) A chemical equation tells us about the substances involved in a reaction.
(b) A chemical equation informs us about the symbols and formulae of the substances involved in a reaction.
(c) A chemical equation tells us about the atoms or molecules of the reactants and products involved in a reaction.
(d) All the above.
Answer. D

Question :  Balance the following chemical equation and identify the reactants and products.

a. _____ Zn (s) + _____ AgNO₃ (aq) → _____ Zn(NO₃)₂ (aq) + _____ Ag (s)
b. _____ N₂ (g) + _____ H₂ (g) → _____ NH₃ (g)
c. _____ Mg(OH)₂ (aq) + _____ H₃PO₄ (aq) → _____ H₂O (l) + _____ Mg₃(PO₄)₂(aq)
d. _____ HNO₃ (aq) + _____ Ni (s) → _____ Ni(NO₃)₂ (aq) + _____ H₂ (g)
e. _____ Ba(HCO₃)₂ (s) → _____ BaCO₃ (s) + _____ H₂O (g) + _____ CO₂ (g)
f. _____ BaCl₂ (aq) + _____ Na₂SO₄ (aq) → _____ NaCl (aq) + _____ BaSO₄ (s)
g. _____ Al2(CO₃)₃ (s) → _____ Al₂O₃ (s) + _____ CO₂ (g)
h. _____ Ca (s) + _____ H₂O (l) → _____ Ca(OH)₂ (aq) + _____ H₂ (g)
i. _____ LiHCO₃ (s) → _____ Li₂CO₃ (s) + _____ H₂O (g) + _____ CO₂ (g)
j. _____ N₂ (g) + _____ O₂ (g) → _____ N₂O₅ (g)
k. _____ MgBr₂ (aq) + _____ KOH (aq) → _____ KBr (aq) + _____ Mg(OH)₂ (s)
l. _____ Mn (s) + _____ CuCl (aq) → _____ Cu (s) + _____ MnCl₂ (s)
m. _____ Zn (s) + _____ S8 (s) → _____ ZnS (s)

Please click the below link to access CBSE Class 10 Chemistry Chemical Reactions And Equations Worksheet Set A