E Z øãç ø Ù ò - StudyMate › media › filer_public › ... · Ba atoms on LHS = 1. Ba atoms on RHS = 3. Step V. To balanced Ba atom, multiply BaCl 2 on LHS by 3. We get 3BaCl

Chemical Reactions and Equations

NCERT Textual Exercise (Solved)

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1. Which of the statements about the reaction below are incorrect? 2PbO(s) + C(s) → 2Pb(s) + CO2(g) (a) Lead is getting reduced. (b) Carbon dioxide is getting oxidised. (c) Carbon is getting oxidised. (d) Lead oxide is getting reduced. (i) (a) and (b) (ii) (a) and (c) (iii) (a), (b) and (c) (iv) all Ans. Statements (a) and (b) are incorrect. Hence, (i) is the correct option. 2. Fe2O3 + 2Al → Al2O3 + 2Fe The above reaction is an example of a : (a) combination reaction (b) double displacement reaction (c) decomposition reaction (d) displacement reaction Ans. The given equation is a displacement reaction in which Fe of Fe2O3 has been

displaced by Al. Hence, (d) is the correct option. 3. What happens when dilute hydrochloric acid is added to Iron fillings? 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. Ans. The following reaction takes place : Fe + 2HCl → FeCl2 + H2 Iron Hydrochloric acid Iron chloride Hydrogen

Thus, hydrogen and iron chloride are produced. Therefore, (a) is the correct option.

4. What is a balanced chemical equation? Why should chemical equations be balanced?

Ans. Balanced chemical equation: An equation in which the number of atoms of each element on the two sides of the equation is equal is called a balanced chemical equation.

According to law of conservation of mass, the total mass of products must be equal to total mass of reactants. This is possible only if the number of atoms of each element is same on the two sides of the equation.



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5. Translate the following statements into chemical equations and then balance them.

(a) Hydrogen gas combines with nitrogen to form ammonia. (b) Hydrogen sulphide gas burns in air to give water and sulphur dioxide. (c) Barium chloride reacts with aluminium sulphate to give aluminium

chloride and a precipitate of barium sulphate. (d) Potassium metal reacts with water to give potassium hydroxide and

hydrogen gas. Ans. (a) Step I. Writing the chemical equation in the word form Nitrogen + Hydrogen → Ammonia Step II. Writing the skeletal chemical equation. N2 + H2 → NH3

Step III. Balancing of atoms on both sides. There are 2 N-atoms on LHS and 1 N atom on RHS. To balance N atoms, multiply NH3 on RHS by 2. We get

N2 + H2 → 2NH3

Now, there are 6 H-atoms on RHS and 2 H atoms on LHS. To balance H-atoms, multiply H2 on LHS by 3. We get N2 + 3H2 → 2NH3

Step IV. To check the correctness of the balanced equation.

LHS RHSN-atoms 2 2H-atoms 6 6

Hence, the equation is balanced. (b) To translate the given statement into chemical equation The word equation for the given statement will be : Hydrogen sulphide + Oxygen → Water + Sulphur dioxide Step I. Writing the skeletal chemical equation H2S + O2 → H2O + SO2

Step II. Balancing the element which occurs at minimum number of places. S and H occur in two compounds whereas O occurs in three compounds. We, therefore, first balance S and H.

S atoms on LHS = 1, S atoms on RHS = 1 H atoms on LHS = 2, H atoms on RHS = 2 Thus, S and H atoms are already balanced.



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Step III. To balance O-atoms : O-atoms on LHS = 2, O-atoms on RHS = 3 (1 in H2O, 2 in SO2) To balance O-atoms, multiply O2 on LHS by 3 and on RHS, H2O

and SO2 by 2 each. We get H2S + 3O2 → 2H2O + 2SO2

Step IV. To rebalance H and S atoms. Now, H-atoms in LHS = 2. H-atoms on RHS = 4. To balance H-atoms, multiply H2S on LHS by 2. We get

2H2S + 3O2 → 2H2O + 2SO2

Now, S-atoms on LHS = 2, S-atoms on RHS = 2 ∴ S-atoms are balanced. Step V. To check that the equation is balanced

Element Atoms on LHS Atoms on RHSH 4 (in 2H2S) 4 (in 2H2O)S 2 (in 2H2S) 2 (in 2SO2)O 6 (in 3O2) 2 (in 2H2O) + 4 (in 2SO2) = 6

Thus, the above equation is the required balanced chemical equation. (c) To translate the given statement into chemical equation Barium chloride + Aluminium sulphate → Aluminium chloride +

Barium sulphate Step I. Writing, the skeletal chemical equation BaCl2 + Al2(SO4)3 → AlCl3 + BaSO4

Balancing of the above equation : Step II. Selecting the biggest formula and balancing of its different

elements. Starting balancing of elements of the compound with the biggest

formula, i.e., Al2(SO4)3, we balance elements one by one as follows: Al atoms on LHS = 2. Al atoms on RHS = 1. Step III. To balance Al atoms, multiply AlCl3 on RHS by 2. We get BaCl2 + Al2(SO4)3 → BaSO4 + 2AlCl3

S atoms on LHS = 3. S atoms on RHS = 1. Step IV. To balance S atoms, multiply BaSO4 on RHS by 3. We get BaCl2 + Al2(SO4)3 → 3BaSO4 + 2AlCl3

O-atoms are automatically balanced.



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Ba atoms on LHS = 1. Ba atoms on RHS = 3. Step V. To balanced Ba atom, multiply BaCl2 on LHS by 3. We get 3BaCl2 + Al2(SO4)3 → 3BaSO4 + 2AlCl3

Cl-atoms are automatially balanced. Step VI. Checking the correctness of the balanced chemical equation.

Element No. of atoms in reactants (LHS)

No. of atoms in products (RHS)

BaClAlSO

3 × 1 = 33 × 2 = 6

23

3 × 4 = 12

3 × 1 = 32 × 3 = 62 × 1 = 23 × 1 = 33 × 4 = 12

Thus, the above equation is the required balanced chemical equation. (d) To translate the given statement into chemical equation. The given

word equation is : Potassium + Water → Potassium hydroxide + Hydrogen In terms of formulae, the skeletal chemical equation will be K + H2O → KOH + H2

Balancing of the above equation : Step I. H atoms occur in maximum compounds. Hence, they should

be balanced last of all. Step II. Balancing of K atoms : Already balanced (1 on each side). Step III. Balancing of O atoms : Already balanced (1 on each side). Step IV. Balancing of H atoms : If we multiply KOH on RHS by

2, number of H-atoms on RHS becomes = 4. To balance H-atoms, multiply H2O on LHS by 2. We get

K + 2H2O → 2KOH + H2

Step V. To re-balance K atoms, multiply K on LHS by 2. We get 2K + 2H2O → 2KOH + H2

This is required balanced equation. 6. Balance the following chemical equations. (a) HNO3 + Ca(OH)2 → Ca(NO3)2 + H2O (b) NaOH + H2SO4 → Na2SO4 + H2O (c) NaCl + AgNO3 → AgCl + NaNO3



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(d) BaCl2 + H2SO4 → BaSO4 + HCl Ans. (a) The given chemical equation is : HNO3 + Ca(OH)2 → Ca(NO3)2 + H2O Step I. Selecting the order of balancing of different elements Here, Ca occurs in two compounds, N in two compounds, H in three

compounds and O in four compounds. Hence, first we will balance Ca and N, then H and O will be balanced

last of all. Balancing of Ca atoms : Already balanced (1 on each side) Balancing of N atoms : N-atoms on LHS = 1, N-atoms on RHS =

2. To balance N-atoms, we multiply HNO3 on LHS by 2. We get 2HNO3 + Ca(OH)2 → Ca(NO3)2 + H2O Balancing of H-atoms : H-atoms on LHS = 2 + 2 = 4. H-atoms on

RHS = 2. To balance H-atoms, we multiply H20 on RHS by 2. We get

2HNO3 + Ca(OH)2 → Ca(NO3)2 + 2H2O Balancing of O-atoms : O-atoms on LHS = 2 × 3 + 2 × 1 = 8 O-atoms on RHS = 3 × 2 + 2 × 1 = 8. Thus, O-atoms are already

balanced. Hence, the above equation is balanced. Step II. Checking the correctness of the balanced equation

Element No. of atoms on LHS No. of atoms on RHSHNOCa

2 × 1 + 2 × 1 = 42 × 1 = 2

2 × 3 + 2 × 1 = 81

2 × 2 = 42 × 1 = 2

2 × 3 + 2 × 1 = 81

Thus, the required balanced equation is 2HNO3 + Ca(OH)2 → Ca(NO3)2 + 2H2O (b) The given chemical equation is NaOH + H2SO4 → Na2SO4 + H2O Step I. Selecting the order of balancing of different elements Na occurs in 2 compounds, O in 4 compounds, H in 3 compounds,

S in 2 compounds. Hence, we will first balance Na and S, then H and finally O.

Balancing of Na : Na atoms on LHS = 1, Na atoms on RHS = 2.



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To balance Na atoms, multiply NaOH on LHS by 2. We get 2NaOH + H2SO4 → Na2SO4 + H2O Balancing of S atoms : Already balanced (1 on each side) Balancing of H atoms : H atoms on LHS = 2 + 2 = 4. H atoms on

RHS = 2. To balance H atoms, multiply H2O on RHS by 2. We get 2NaOH + H2SO4 → Na2SO4 + 2H2O Balancing of O - atoms : O-atoms on LHS = 2 + 4 = 6. O-atoms on RHS = 4 + 2 = 6. Thus, O-atoms are already balanced. Hence, the above equation is balanced. Step II. Checking the correctness of the balanced equation

Element No. of atoms on LHS No. of atoms on RHSNaOHS

22 + 4 = 62 + 2 = 4

1

24 + 2 = 62 × 2 = 4

1 Thus, the required balanced equation is 2NaOH + H2SO4 → Na2SO4 + 2H2O (c) The given chemical equation is NaCl + AgNO3 → AgCl + NaNO3

Listing the number of atoms of different elements

Element No. of atoms on LHS No. of atoms on RHSNaClAgNO

11113

11113

Thus, the number of atoms of different elements are equal on the two sides. Hence, the given equation is a balanced equation

(d) The given chemical equation is BaCl2 + H2SO4 → BaSO4 + HCl Step I. Selecting the order of balancing of different elements Each element is present in two compounds. Hence, they can be

balanced in any order. Balancing of Ba atoms : Already balanced (1 on each side)



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Balancing of Cl atoms : Cl-atoms on LHS = 2. Cl-atoms on RHS = I. To balance Cl atoms, multiply HCl on RHS by 2. We get

BaCl2 + H2SO4 → BaSO4 + 2HCl Balancing of S - atoms : Already balanced (1 on each side) Balancing of H - atoms : Already balanced (2 on each side) Hence, the above equation is balanced. Step II. Checking the correctness of the balanced equation

Element No. of atoms on LHS No. of atoms on RHSBaClHSO

12214

12214

Thus, the required balanced equation is BaCl2 + H2SO4 → BaSO4 + 2HCl 7. Write the balanced chemical equations for the following reactions. (a) Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water (b) Zinc + Silver nitrate → Zinc nitrate + Silver (c) Aluminium + Copper chloride → Aluminium chloride + Copper (d) Barium chloride + Potassium sulphate → Barium sulphate +

Potassium chloride Ans. (a) Step I. Writing the skeletal chemical equation Ca(OH)2 + CO2 → CaCO3 + H2O Step II. Listing number of atoms of different elements.

Element No. of atoms on LHS No. of atoms on RHSCaO

HC

12 in Ca(OH)2 + 2 in CO2

= 42 in Ca(OH)2

1 in CO2

13 in CaCO3 + 1 in H2O

= 42 in H2O

1 in CaCO3

Thus, number of atoms of each element is equal on the two sides. Hence, the above equation is the balanced chemical equation.

(b) Step I. Writing the skeletal chemical equation Zn + AgNO3 → Zn(NO3)2 + Ag



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Step II. Balancing of different elements Zn and Ag atoms are already balanced. To balance N atoms, multiply

AgNO3 on LHS by 2. We get Zn + 2AgNO3 → Zn(NO3)2 + Ag To balance Ag atoms, multiply Ag on RHS by 2. We get Zn + 2AgNO3 → Zn(NO3)2 + 2Ag O-atoms are automatically balanced. Thus, the above equation is balanced. Step III. Checking the correctness of the balanced equation

Element No. of atoms on LHS No. of atoms on RHSZnAgNO

1226

1226

Thus, the required balanced chemical equation is Zn + 2AgNO3 → Zn(NO3)2 + 2Ag (c) Step I. Writing the skeletal chemical equation Al + CuCl2 → AlCl3 + Cu Step II. Balancing of different elements Balancing of Al atoms : Already balanced (1 on each side) Balancing of Cl atoms : Cl atoms on LHS = 2. Cl atoms on RHS

= 3 To balance Cl atoms, multiply ZnCl2 on LHS by 3 and AlCl3 on RHS

by 2. We get Al + 3CuCl2 → 2AlCl3 + Cu Rebalancing of Al atoms : Now, Al atoms on LHS = 1. Al atoms

on RHS = 2 To balance Al atoms, multiply Al on LHS by 2. We get 2Al + 3CuCl2 → 2AlCl3 + Cu Balancing of Cu atoms : Cu atoms on LHS = 3. Cu atoms on RHS

= 1 To balance Cu atoms, multiply Cu on RHS by 3. We get 2Al + 3CuCl2 → 2AlCl3 + 3Cu Thus, the above equation is balanced.



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Step III. Checking the correctness of the balanced equation

Element No. of atoms on LHS No. of atoms on RHSAlCuCl

236

236

Hence, the required balance equation is 2Al + 3CuCl2 → 2AlCl3 + 3Cu (d) Step I. Writing the skeletal chemical equation BaCl2 + K2SO4 → BaSO4 + KCl Step II. Balancing of different elements Balancing of Ba atoms : Ba atom on LHS = 1, Ba atoms on RHS

= 1 Hence, Ba atoms are already balanced. Balancing of Cl atoms : Cl atoms on LHS = 2, Cl atoms on RHS

= 1 To balance Cl atoms, multiply KCI on RHS by 2. We get BaCl2 + K2SO4 → BaSO4 + 2KCl Balancing of K atoms : Already balanced (2 on each side) Balancing of O atoms : Already balanced (4 on each side) Hence, the above equation is balanced. Step III. Checking the correctness of the balanced equation

Element No. of atoms on LHS No. of atoms on RHSBaClKSO

12214

12214

Thus, the required balanced equation is BaCl2 + K2SO4 → BaSO4 + 2KCl 8. Write the balanced chemical equation for the following and identify the type

of reaction in each case. (a) Potassium bromide(aq) + Barium iodide(aq) → Potassium iodide(aq)

+ Barium bromide(s) (b) Zinc carbonate(s) → Zinc oxide(s) + Carbon dioxide(g)



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(c) Hydrogen(g) + Chlorine(g) → Hydrogen chloride(g) (d) Magnesium(s) + Hydrochloric acid(aq) → Magnesium chloride(aq)

+ Hydrogen(g) Ans. (a) Step I. Writing the skeletal chemical equation The skeletal chemical equation will be KBr + BaI2 → KI + BaBr2

Step II. Listing number of atoms of different elements.

Element No. of atoms on LHS

No. of atoms on RHS

Balanced/Unbalanced

KBrBaI

1112

1211

BalancedUnbalanced

BalancedUnbalanced

Step III. Balancing of different elements To balance the number of Br atoms, multiply KBr on LHS by 2. We

get 2KBr + BaI2 → KI + BaBr2 To balance the number of I atoms, multiply KI on RHS by 2. We get 2KBr + BaI2 → 2KI + BaBr2 Step IV. Writing with the state symbols. We have 2KBr (aq) + BaI2 (aq) → 2KI (aq) + BaBr2 (aq) Step V. Checking the correctness of the balanced equation On checking, the number of atoms of each element are equal on the

two sides. Hence, this is the required balanced chemical equation. As both the anions exchange their positions, it is a double

displacement reaction. (b) Step I. Writing the skeletal chemical equation The skeletal chemical equation will be ZnCO3 (s) → ZnO (s) + CO2 (g) Step II. Listing the number of atoms of different elements


No. of atoms on RHS

Balanced/Unbalanced

ZnCO

113

113

BalancedBalancedBalanced



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Thus, the number of atoms of each element is equal on the two sides. Hence, the above equation is the required balanced equation.

As a single compound decomposes to form two simpler substances, it is a decomposition reaction.

(c) Step I. Writing the skeletal chemical equation H2 (g) + Cl2 (g) → HCl (g) Step II. Balancing of different elements To balance H, multiply HCl on RHS by 2. We get H2 (g) + Cl2 (g) → 2HCl (g) Cl atoms are automatically balanced. This is the required balanced chemical equation. As two substances combine to form a single compound, it is a

combination reaction. (d) Step I. Writing the skeletal chemical equation Mg (s) + HCl (aq) → MgCl2 (aq) + H2 (g) Step II. Listing the number of atoms of different elements


No. of atoms on RHS

Balanced/Unbalanced

MgHCl

111

122

BalancedUnbalancedUnbalanced

Step III. Balancing of different elements To balance H atoms, multiply HCl on LHS by 2. We get Mg + 2HCI → MgCl2 + H2

Cl-atoms are automatically balanced. Step IV. Writing with the state symbols. We have Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g) Step V. Checking the correctness of the balanced equation 9. What does one mean by exothermic and endothermic reactions? Give

examples. Ans. (i) Exothermic reactions: Those reactions in which heat is evolved

during the reaction are called exothermic reactions. Example, (a) Burning of coke C + O2 → CO2 + Heat Coke Oxygen (from air) Carbon dioxide



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(b) Burning of natural gas (methane) CH4 + 2O2 → CO2 + 2H2O + Heat Methane Oxygen Carbon Water (from air) dioxide

(c) Oxidation of glucose in the cells of our body C6H12O6 + 6O2 → 6CO2 + 6H2O + Heat Glucose Oxygen Carbon Water dioxide (ii) Endothermic reactions: Those reactions in which energy is absorbed

or provided during the reaction are called endothermic reactions. Example,

(a) Reaction of coke with stream C + H2O + Heat → CO + H2 Coke Steam Carbon Hydrogen monoxide (b) Combination of nitrogen and oxygen to form nitric oxide N2 + O2 + Heat → 2NO Nitrogen Oxygen Nitric oxide

(c) Decomposition of mercuric oxide 2HgO + Heat → 2Hg + O2 Mercuric Mercury Oxygen oxide

10. Why is respiration considered an exothermic reaction? Explain. Ans. Rice, potatoes, bread etc., that we eat contain starch. On digestion, it breaks

down into glucose. The air we breathe in during respiration oxidizes glucose into carbon dioxide and water with the liberation of heat which provides our body with the required energy. Hence, respiration is considered as an exothermic reaction.

11. Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.

Ans. In a decomposition reaction, a single compound splits to give two or more simpler substances whereas in a combination reaction, two or more simpler substances combine together to form a single compound. Hence, they are opposite to each other.

Examples of decomposition reactions : (i) CaCO3

Heat → CaO + CO2 Calcium Calcium Carbon carbonate oxide dioxide

(ii) 2Pb(NO3)2 Heat → 2PbO + 4NO2 + O2

Lead nitrate Lead oxide Nitrogen dioxide Oxygen



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(iii) 2FeSO4 Heat → Fe2O3 + SO2 + SO3

Ferrous sulphate Ferric oxide Sulphur dioxide Sulphur trioxide Example of combination reactions : (i) 2Mg + O2 → 2MgO Magnesium Oxygen Magnesium oxide

(ii) CaO + H2O → Ca(OH)2 Quick lime Water Slaked lime

(iii) 2H2 + O2 → 2H2O Hydrogen Oxygen Water

12. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.

Ans. (i) Decomposition reaction involving absorption of heat CaCO3

Heat → CaO + CO2 Lime stone Quick lime Carbon dioxide

(ii) Decomposition reaction involving absorption of light 2AgCl Sunlight → 2Ag + Cl2 Silver chloride Silver Chlorine

or, 2H2O2 Light → 2H2O + O2

Hydrogen peroxide water Oxygen

(iii) Decomposition reaction involving absorption of electrical energy

2H2O Electriccurrent → 2H2 + O2

13. What is the difference between displacement and double displacement reactions? Write equations for these reactions.

Ans. Displacement reaction means single displacement reaction where more active element displaces a less active element from the solution of its salt. For example,

(i) Zn + CuSO4 → ZnSO4 + Cu Zinc Copper sulphate Zinc sulphate Copper

(ii) Cl2 + 2KI → 2KCl + I2 Chlorine Potassium iodide Potassium chloride Iodine

In reaction (i), zinc has displaced copper from CuSO4. In reaction (ii), chlorine has displaced iodine from KI. Double displacement reactions are those reactions in which the solutions of

two ionic compounds react in such a way that both the anions are exchanged.



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For example, (i) BaCl2 + Na2SO4 → BaSO4 + 2NaCl Barium chloride Sodium sulphate Barium sulphate Sodium chloride

(ii) AgNO3 + NaCl → AgCl + NaNO3 Silver nitrate Sodium chloride Silver chloride Sodium nitrate

In reaction (i), chloride ions of BaCl2 are replaced by sulphate ions of Na2SO4 and sulphate ions of Na2SO4 are replaced by chloride ions of BaCl2. Similarly, in reaction (ii), nitrate ions (NO–

3) and chloride ions (Cl–) are exchanged. 14. In the refining of silver, the recovery of silver from silver nitrate solution

involved displacement by copper metal. Write down the reaction involved. Ans. Cu + 2AgNO3 → Cu(NO3)2 + 2Ag Copper Silver nitrate Copper (II) nitrate Silver

15. What do you mean by a precipitation reaction? Explain by giving examples. Ans. When on mixing the clear solutions of two ionic compounds, an insoluble

solid is formed that separates out, the solid formed is called a precipitate and the reaction is called a precipitation reaction.

(i) BaCl2 + Na2SO4 → BaSO4 + 2NaCl Barium chloride Sodium sulphate Barium sulphate Sodium chloride

(ii) AgNO3 + NaCl → AgCl + NaNO3 Silver nitrate Sodium chloride Silver chloride Sodium nitrate

16. Explain the following in terms of gain or loss of oxygen with two examples each.

(a) Oxidation (b) Reduction Ans. (a) Oxidation: It is defined as a process which involves gain of oxygen.

For example, (i) 2Mg + O2 → 2MgO Magnesium Oxygen Magnesium oxide

Here, Mg has gained oxygen to form MgO. Hence, Mg has been oxidized to MgO.

(ii) CuO + H2 → Cu + H2O Copper oxide Hydrogen Copper Water

Here, H2 has gained oxygen to form H2O. Hence, H2 has been oxidized to H2O.

(b) Reduction: It is defiend as a process which involves loss of oxygen. For example,

(i) ZnO + C Heat → Zn + CO Zinc oxide Carbon Zinc Carbon monoxide



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Here, ZnO has lost oxygen to form Zn. Hence, ZnO has been reduced to Zn.

(ii) 2Fe2O3 + 4Al Heat → 4Fe + 2Al2O3 Ferric Aluminium Iron Aluminium oxide oxide

Here, Fe2O3 has lost oxygen to form Fe. Hence, Fe2O3 has been reduced to Fe.

17. A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.

Ans. The element ‘X’ must be copper because copper is a shiny brown coloured element which on heating in air, combines with oxygen of the air to form black copper oxide.

2Cu + O2 → 2CuO Copper (from air) Oxygen (black) Copper (II) oxide Thus, black coloured compound formed is copper (II) oxide, CuO. 18. Why do we apply paint on iron articles? Ans. Paint covers the surface of the iron articles. Hence, moist air cannot come

directly in contact with iron. As a result, it cannot attack iron and prevents rusting.

19. Oil and fat containing food items are flushed with nitrogen. Why? Ans. In the presence of oxygen of the air, the fats present in the fatty food are

oxidized to compounds which have a bad smell, i.e., the food becomes rancid. Flushing with nitrogen cuts off oxygen and protects the food from rancidity.

20. Explain the following terms with one example each. (a) Corrosion (b) Rancidity Ans. (a) Corrosion: Corrosion is defined as a process where materials,

usually metals, deteriorate as a result of a chemical reaction with air, moisture, chemicals, etc.

For example, iron, in the presence of moisture, reacts with oxygen to form hydrated iron oxide.

4Fe + 3O + H O 2Fe O . H O2 2 2 3 2Hydrated Iron oxide

n n→

This hydrated iron oxide is rust. (b) Rancidity: The process of oxidation of fats and oils that can be easily

noticed by the change in taste and smell is known as rancidity. For example, the taste and smell of butter changes when kept for long.

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E Z øãç ø Ù ò - StudyMate › media › filer_public › ... · Ba atoms on LHS = 1. Ba atoms on RHS = 3. Step V. To balanced Ba atom, multiply BaCl 2 on LHS by 3. We get 3BaCl