NCERT Book Class 10 Science Chemical Reactions and Equations Answers

Question. Which of the following is an example of oxidation reaction ?
(A) Sn⁺² – 2e^- → Sn⁺⁴
(B) Fe⁺³ + e- → Fe⁺²
(C) Cl² + 2e^– → 2Cl^-
(D) None of these
Answer : A

Question. Which of the following reactions is/are a double displacement reaction(s) ?
(i) AgNO₃ + NaBr → NaNO₃ + AgBr (ii) BaCl₂ + H₂SO₄ → BaSO₄ + 2HCl
(iii) As₂O₃ + 3H₂S → As₂S₃ + 3H₂O (iv) NaOH + HCl → NaCl + H₂O
(A) (i) & (ii)
(B) only (iii)
(C) only (iv)
(D) (i) to (iv) all
Answer : D

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. 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. On heating ferrous sulphate crystal, one would get :
(A) Sweet smell
(B) Rotten egg smell
(C) Smell of burning sulphur
(D) No solid residue
Answer : C

Question. AgNO₃ (aq) + NaCl (aq) → AgCl(s) + NaNO₃(aq) Above reaction is a -
(A) precipitation reaction
(B) double displacement reaction
(C) combination reaction
(D) (A) and (B) both
Answer : D

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. The reaction between aqueous solutions of sodium chloride and silver nitrate is -
(A) Displacement reaction
(B) Synthesis reaction
(C) Double displacement reaction
(D) Analysis reaction
Answer : C

Question. CH₄ + Cl₂ → CH₃Cl + HCl reaction is an example of -
(A) Synthetic
(B) Analytical
(C) Displacement
(D) Neutralisation
Answer : C

Question. A Brown and bright element “x” when heated in presence of air turns into black substance “y”. If Hydrogen gas is passed over this heating material again “x” is obtained. “x” and “y” are –
(A) Cu & CuO
(B) S & SO₂
(C) C & CO₂
(D) Na & NaH
Answer : A

Question. H₂S(g) + Cl₂(g) → 2 HCl(g) + S(s)
The reaction is interpreted as :
(A) H₂S is getting oxidised and Cl₂ is getting reduced
(B) H₂S is getting reduced and Cl₂ is getting oxidised
(C) Only H₂S is oxidised
(D) Both H₂S and Cl₂ are reduced
Answer : A

Question. Oxidation is defined as :
(A) Loss of electron
(B) Gain of electron
(C) Loss of proton
(D) Gain of proton
Answer : A

Question. From the following metals whose nitrate produces NO₂ gas on heating
(A) Na
(B) K
(C) Pb
(D) None of these
Answer : C

Question. Displacement reaction is : 
(A) CaO (s) + H₂O(l) → Ca(OH)₂ (aq)
(B) Pb(s) + CuCl₂(aq) → PbCl₂(aq) + Cu(s)
(C) MnO₂(s) + 4HCl(l) → MnCl₂\(s) + 2H₂O(l) + Cl₂(g)
(D) C6H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
Answer : B

Question. Which of the following is endothermic reaction ?
(A) C(s) + O₂(g) → CO₂(g)
(B) N₂(g) + O₂(g) → 2NO(g)
(C) 2H₂(g) + O₂(g) → 2H₂O(l)
(D) 2CH₂OH (l) + 3O₂(g) → 2CO₂(g)+₄H₂O(l)
Answer : B

Question. Precipitate formation during chemical reaction is indicated by this arrow :
(A) ↑
(B) →
(C) ↓
(D) ←
Answer : C

Question. BaCl₂(aq) + Na₂SO₄ (aq) → BaSO₄(s) + 2NaCl(aq) 
The types of reaction are :
(a) Displacement
(b) Precipitation
(c) Combination
(d) Double displacement
(A) (a) & (c)
(B) (a), (b), & (c)
(C) (b) & (c)
(D) (b) & (d)
Answer : D

Question. The chemical reaction HNO₃ + KOH → KNO₃ + H₂O is an example of 
(A) Neutralization
(B) Double displacement
(C) Neutralization and double displacement
(D) Combination
Answer : C

Question. Hydrolysis of water is which type of following reactions?
(A) Endothermic
(B) Decomposition
(C) Both A and B
(D) Combination
Answer : C

Question. When a burning splinter is brought near the gas jar containing hydrogen gas a popping sound is observed. It is due to
(A) exothermic
(B) endothermic
(C) exothermic and endothermic
(D) none of these
Answer : A

Question. Match the given column-I with column-II and choose the correct option :
                I                                                 II
a. 2Mg + O₂ → 2MgO             i. Exothermic reaction
b. CaO+H₂O → Ca(OH)₂       ii. Dissociation 
c. 2 AgCl → 2Ag + Cl₂            iii. Reduction
d. CuO +H₂ → Cu+H₂O         iv. Oxidation
(A) a-i, b-ii, c-iii, d-iv
(B) a-ii, b-i, c-iv, d-iii
(C) a-iv, b-iii, c-i, d-ii
(D) a-iv, b-i, c-ii, d-iii
Answer : D

Question. Identify the type of reaction for each of the following as [A. P. NTSE Stage-1/ 2015]
Combination – (p)
Decomposition – (q)
Displacement – (r)
Double displacement – (s)
Combustion – (t)
(i) A compound breaks apart into its elements
(ii) A metal and a non-metal react to form an ionic compound.
(iii) A compound of Hydrogen and Carbon reacts with Oxygen to produce Carbon-dioxide and water
(iv) Silver ion from Ag(NO3) (aq.) forms a precipitate with bromide ion from KBr aq.
(A) (i) – q (ii) – p (iii) – r (iv) - s
(B) (i) – q (ii) – p (iii) – t (iv) - s
(C) (i) – s (ii) – r (iii) – q (iv) - p
(D) (i) – p (ii) – t (iii) – q (iv) – r
Answer : B

Question. Container made of Copper metal on exposure to air for longtime turns green. The green layer is due to 
(A) CuO
(B) CuCO₃.Cu(OH)₂
(C) CuSO₄. 3Cu(OH)₂
(D) All of the above
Answer : B

Question. All of the following processes involve a separation of either a mixture into its components, or a compound into elements. For each, decide whether a physical process or a chemical reaction is required. 
a. Sodium metal is obtained from the substance sodium chloride.
b. Iron fillings are separated from sand by using a magnet.
c. Sugar crystals are separated from sugar syrup by evaporation of water.
d. Fine crystals of silver chloride are separated from a suspension of the crystals in water.
e. Copper is produced when zinc metal is placed in a solution of copper (II) sulphate, a compound.
Physical processes          Chemical processes.
(A) a, b, c                                     d, e
(B) a, d                                         b,c,e
(C) b, c, d                                     a, e
(D) c                                             a, b, c, d
Answer : C

Question. Addition of HCl to an aqueous solution of Pb(NO₃)₂ gives a
(A) Yellow Precipitate
(B) Brown Precipitate
(C) White Precipitate
(D) Black Precipitate
Answer : C

Question. The oxidation reaction in the following chemical changes is 
(A) Cl + e^– → Cl^–
(B) Mg⁺² + 2e^– → Mg
(C) MnO₄– + e^– → MnO₄^–2
(D) Fe⁺² → Fe⁺³ + e^–
Answer : D

Question. Which of the following reaction is a displacement reaction?
(A) 2KClO₃ → 2KCl + 3O₂
(B) 2H₂ + O₂ → 2H₂O
(C) Zn + 2HCl → ZnCl₂ + H₂
(D) N₂ + 3H₂ → 2NH₃
Answer : A

Question. When steam is passed over red hot coke, which gas is formed ?
(A) CO₂
(B) CO + H₂
(C) NH₃
(D) CO + N₂
Answer : B

Question. Which of the following are combination reactions ?
(i) 2KClO₃ → 2KCl + 3O₂ (ii) MgO + H₂O → Mg(OH)₂
(iii) 4Al + 3O₂ → 2Al₂O₃ (iv) Zn + FeSO₄ → ZnSO₄ + Fe
(A) (i) and (iii)
(B) (iii) and (iv)
(C) (ii) and (iv)
(D) (ii) and (iii)
Answer : D

Question. In balanced chemical equation a KMnO₄ + b H₂SO₄ → c K₂SO₄ + d MnSO₄ + e H₂O + f[O]
Which of the following alternative are correct?
(A) a = 2, b = 3, c = 1, d = 2, e = 3, f = 5
(B) a = 1, b = 2, c = 1, d = 3, e = 2, f = 3
(C) a = 2, b = 3, c = 2, d = 3, e = 2, f = 5
(D) a = 3, b = 1, c = 3, d = 3, e = 1, f = 3
Answer : A

Question. Which of the following reactions is not a redox reaction ? 
(A) Mg + Cl₂ → MgCl₂
(B) CuO + H₂ → Cu + H₂O
(C) AgNO₃ + NaCl → AgCl + NaNO₃
(D) MnO₂ + 4HCl → MnCl₂ + 2H₂O + 2Cl₂
Answer : C

Question. Corrosion and rancidity are due to ___________ and ___________ respectively.
(A) oxidation ; oxidation
(B) oxidation ; reduction
(C) reduction ; oxidation
(D) reduction ; reduction
Answer : A

Question. A green substance "X", when heated strongly produces a brown solid and gas “Y”. The gas is passed into caustic soda and then the solution is treated with BaCl₂ to get a white solid "Z" Identify 'X', 'Y', 'Z’ and choose the correct answer of their formula : 
(A) FeSO₄ .7H₂O, SO₃, BaSO₄
(B) CuSO₄.5H₂O, SO₂, Cu(OH)₂
(C) CuSO₄.5H₂O, SO₃,, BaSO₄
(D) FeSO₄.7H₂O, SO₃, Fe(OH)₃
Answer : A

Question. Which among the following is not a redox reaction ?
(A) 2Na(s) + Cl₂(g) → 2NaCl(s)
(B) Ca(OH)₂(aq) + 2HNO₃(aq) → Ca(NO₃)₂ (aq) + 2H₂O(l)
(C) 2Pb(NO₃)₂(s) → 2PbO(s) + 4NO₂(g) + O₂(g)
(D) Cl₂(g) + H₂O(l) → HCl(aq) + HClO(aq)
Answer : B

Question. Which ammonium compound does not produce ammonia gas on heating ?
(A) (NH₄)₂SO₂
(B) (NH₄)₂CO₃
(C) NH4NO₂
(D) NH4Cl
Answer : C

Please refer to attached file for NCERT Class 10 Science Chemical Reactions and Equations Answers