Write what happened in the following reactions in the table below. State which one is oxidation and which one is reduction. Equations of the reactions What happened Oxidation or reduction (i) Fe 3 + + e - → Fe 2 + (ii) Cl - → Cl + e - (iii) MnO 4 2 - → MnO 4 - + e - (iv) Cu 2 + + 2 e - → Cu

Completed table is: Equations of the reactions What happened Oxidation or reduction (i) Fe 3 + + e - → Fe 2 + Here, Fe 3 + accepts one electron and forms Fe 2 + . Reduction (ii) Cl - → Cl + e - In this reaction, Cl - eliminates electron and forms chlorine atom. Oxidation (iii) MnO 4 2 - → MnO 4 - + e - In this reaction, MnO 4 2 - eliminate electron and forms MnO 4 - . Oxidation (iv) Cu 2 + + 2 e - → Cu In this reaction, Cu 2 + accepts two electrons and form copper atom. Reduction

Equation Oxidation reaction Reduction reaction Oxidant Reductant Concept that you used to reach your conclusion H 2 S + 2FeCl 3 → 2HCl + S + 2FeCl 2 2Na + H 2 → 2NaH 2Na → 2Na + +2e - H 2 + 2e - → 2H - Zn + CuSO 4 → ZnSO 4 + Cu FeO + CO → Fe + CO 2 FeSO 4 + Zn → ZnSO 4 + Fe

Oxidation reactions involve addition of oxygen or chlorine, elimination of hydrogen or electron. Reduction reactions involve elimination of oxygen or chlorine, addition of hydrogen or electron. Equation Oxidation reaction Reduction reaction Oxidant Reductant Concept that you used to reach your conclusion H 2 S + 2FeCl 3 → 2HCl + S + 2FeCl 2 S 2- → S +2e - 2Fe 3+ + 2e - → 2Fe 2+ FeCl 3 H 2 S Elimination of Cl from FeCl 3 2Na + H 2 → 2NaH 2Na → 2Na + +2e - H 2 + 2e - → 2H - H 2 Na Addition of H to Na Zn + CuSO 4 → ZnSO 4 + Cu Cu 2+ + 2e - → Cu Zn + 2e - → Zn 2+ CuSO 4 Zn Addition of O to Zn FeO +CO → Fe + CO 2 C 2+ - 2e - → C Fe 2+ + 2e - → Fe FeO CO Addition of O to CO FeSO 4 + Zn → ZnSO 4 + Fe Zn - 2e - → Zn 2+ Fe 2+ + 2e - → Fe FeSO 4 Zn Addition of O to Zn

Write down the nature of oxidants and reductants from the given examples: CuO ( Oxidant ) + H 2 ( Reductant ) → Cu + H 2 O MnO 2 ( Oxidant ) + 4 HCl ( Reductant ) → MnCl 2 + Cl 2 + 2 H 2 O Cl 2 ( Oxidant ) + 2 HBr ( Reductant ) → 2 HCl + Br 2 Type of substance Name and formulae Element or compound

CuO ( Oxidant ) + H 2 ( Reductant ) → Cu + H 2 O Here, hydrogen gets oxidized to form water. Type of substance Name and formulae Element or compound Oxidant Copper oxide, CuO Compound Reductant Hydrogen, H 2 Element MnO 2 ( Oxidant ) + 4 HCl ( Reductant ) → MnCl 2 + Cl 2 + 2 H 2 O Here, HCl gets oxidized and chlorine is formed. Type of substance Name and formulae Element or compound Oxidant Manganese dioxide, MnO 2 Compound Reductant Hydrochloric acid, HCl Compound Cl 2 ( Oxidant ) + 2 HBr ( Reductant ) → 2 HCl + Br 2 Here chlorine is reduced to form hydrogen chloride. Type of substance Name and formulae Element or compound Oxidant Chlorine, Cl 2 Element Reductant Hydrogen bromide, HBr Compound

MEDIUM

8th West Bengal Board

IMPORTANT

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From the following reaction, identify the substance that has undergone oxidation and the substance that has undergone reduction.

Equation of reaction Substance oxidised Substance reduced Reason behind your answer

$2 {SO}_{2} + O_{2} \to 2 {SO}_{3}$

Important Questions on Element, Compound and Chemical Reaction

MEDIUM

8th West Bengal Board

IMPORTANT

Environment and Science Class 8>Chapter 2 - Element, Compound and Chemical Reaction>Exercise 13>Q ii)

From the following reaction, identify the substance that has undergone oxidation and the substance that has undergone reduction.

Equation of reaction	Substance oxidised	Substance reduced	Reason behind your answer
${Fe}_{2} O_{3} + 3 CO \to 2 Fe + 3 {CO}_{2}$

MEDIUM

8th West Bengal Board

IMPORTANT

Environment and Science Class 8>Chapter 2 - Element, Compound and Chemical Reaction>Exercise 13>Q iii)

From the following reaction, identify the substance that has undergone oxidation and the substance that has undergone reduction.

Equation of reaction	Substance oxidised	Substance reduced	Reason behind your answer
$ZnO + C \to Zn + CO$

MEDIUM

8th West Bengal Board

IMPORTANT

Environment and Science Class 8>Chapter 2 - Element, Compound and Chemical Reaction>Exercise 13>Q iv)

From the following reaction, identify the substance that has undergone oxidation and the substance that has undergone reduction.

Equation of reaction	Substance oxidised	Substance reduced	Reason behind your answer
$2 {FeCl}_{3} + H_{2} S \to 2 {FeCl}_{2} + 2 HCl + S ↓$

MEDIUM

8th West Bengal Board

IMPORTANT

Environment and Science Class 8>Chapter 2 - Element, Compound and Chemical Reaction>Exercise 13>Q v)

From the following reaction, identify the substance that has undergone oxidation and the substance that has undergone reduction.

Equation of reaction	Substance oxidised	Substance reduced	Reason behind your answer
$FeO + H_{2} \to Fe + H_{2} O$

MEDIUM

8th West Bengal Board

IMPORTANT

Environment and Science Class 8>Chapter 2 - Element, Compound and Chemical Reaction>Exercise 13>Q vi)

From the following reaction, identify the substance that has undergone oxidation and the substance that has undergone reduction.

Equation of reaction	Substance oxidised	Substance reduced	Reason behind your answer
${Fe}_{2} O_{3} + Al \to 2 Fe + {Al}_{2} O_{3}$

MEDIUM

8th West Bengal Board

IMPORTANT

Environment and Science Class 8>Chapter 2 - Element, Compound and Chemical Reaction>Exercise 14>Q (i)

Write what happened in the following reactions in the table below. State which one is oxidation and which one is reduction.

Equations of the reactions	What happened	Oxidation or reduction
(i) ${Fe}^{3 +} + e^{-} \to {Fe}^{2 +}$
(ii) ${Cl}^{-} \to Cl + e^{-}$
(iii) ${MnO}_{4}^{2 -} \to {MnO}_{4}^{-} + e^{-}$
(iv) ${Cu}^{2 +} + 2 e^{-} \to Cu$

MEDIUM

8th West Bengal Board

IMPORTANT

Environment and Science Class 8>Chapter 2 - Element, Compound and Chemical Reaction>Exercise 15>Q 1

Equation	Oxidation reaction	Reduction reaction	Oxidant	Reductant	Concept that you used to reach your conclusion
H₂S + 2FeCl₃ $\to$ 2HCl + S + 2FeCl₂
2Na + H₂ $\to$ 2NaH	2Na $\to$ 2Na⁺ +2e^-	H₂ + 2e^{- $\to$}2H^-
Zn + CuSO₄ $\to$ ZnSO₄ + Cu
FeO + CO $\to$ Fe + CO₂
FeSO₄ + Zn $\to$ ZnSO₄ + Fe

HARD

8th West Bengal Board

IMPORTANT

Environment and Science Class 8>Chapter 2 - Element, Compound and Chemical Reaction>Exercise 16>Q 1

Write down the nature of oxidants and reductants from the given examples:

$\underset{(Oxidant)}{CuO} + \underset{(Reductant)}{H_{2}} \to Cu + H_{2} O$

$\underset{(Oxidant)}{{MnO}_{2}} + \underset{(Reductant)}{4 HCl} \to {MnCl}_{2} + {Cl}_{2} + 2 H_{2} O$

$\underset{(Oxidant)}{{Cl}_{2}} + \underset{(Reductant)}{2 HBr} \to 2 HCl + {Br}_{2}$

Type of substance	Name and formulae	Element or compound

From the following reaction, identify the substance that has undergone oxidation and the substance that has undergone reduction. Equation of reaction Substance oxidised Substance reduced Reason behind your answer 2SO2+O2→2SO3

Important Questions on Element, Compound and Chemical Reaction

Learn and Prepare for any exam you want !

From the following reaction, identify the substance that has undergone oxidation and the substance that has undergone reduction.

Equation of reaction Substance oxidised Substance reduced Reason behind your answer

$2 {SO}_{2} + O_{2} \to 2 {SO}_{3}$