Maharashtra Board Class 10 Science Part – 1 Chapter 3 Chemical Reaction And Equation Solution

Maharashtra Board Class 10 Science Part – 1 Solution Chapter 3 – Chemical Reaction And Equation

Balbharati Maharashtra Board Class 10 Science Part – 1 Solution Chapter 3: Chemical Reaction And Equation. Marathi or English Medium Students of Class 10 get here Chemical Reaction And Equation full Exercise Solution.

Std	Maharashtra Class 10
Subject	Science Part – 1 Solution
Chapter	Chemical Reaction And Equation

 

Chapter: -3

(Chemical Reaction And Equation)

 

Exercise:-

 

1) Choose the correct option from the bracket and explain the statement giving reason.

(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)

a) To prevent rusting, a layer of …zinc…..metal is applied on iron sheets.

Reason: – A non-corrosive metal needed to prevent rusting just like zinc.

 

b) The conversion of ferrous sulphate to ferric sulphate is ..an oxidation…… reaction. Reason: – Fe+2 become Fe+3 so it gets oxidized.

 

c) When electric current is passed through acidulated water .. electrolysis…… of water takes place.Reason: -Water get decomposed in hydrogen and oxygen and the hydrogen will form at cathode and oxygen in anode.

 

d) Addition of an aqueous solution of ZnSO4 to an aqueous solution of BaCl2 form a white precipitate is an example of …double displacement…. reaction. Reason: – As precipitate are from in this reaction with help of ion exchange.

 

2) Write answers to the following.

 

a) What is the reaction called when oxidation and reduction take place simultaneously? Explain with one example.

Ans: – When oxidation and reduction take places simultaneously then this reaction is known as redox reaction.

Example : – Cu0 + H2 —> H2O + Cu. In this reaction CuO loses oxygen and H2 from water after taking it.

 

b) How can the rate of the chemical reaction, namely, decomposition of hydrogen peroxide be increased?

Ans: – The rate of reaction or decomposition of hydrogen peroxide increased with the help of iodine ion in two step.

First step is H2O2 (aq) + I+ —> H2O + IO- .(aq) and the next stage is IO- + H2O2 à H2O + O2(g) + I-.

 

c) Explain the term reactant and product giving examples.

Ans: – The reactant is which takes part in the chemical reaction. And the final substance of any chemical reaction is known as product.

Example: – 2Na + 2Cl —> 2NaCl. Here Na and Cl is reactants and NaCl is product.

 

d) Explain the types of reaction with reference to oxygen and hydrogen. Illustrate with examples.

Ans: – Hydrogen and oxygen takes part in different types of reaction like combination reaction (  2H2 + O2 = 2H2O) , decomposition reaction ( 2H2O —> 2H2 + O2), oxidation and reduction.

 

e) Explain the similarity and difference in two events, namely adding NaOH to water and adding CaO to water.

Ans: – The reaction between sodium hydroxide and water is NaOH + H2O —> Na+ (aq) + O. And the reaction between water and calcium hydroxide is CaO + H2O —> Ca(OH)2.

From the upper reaction we find that both equation is exothermic in nature but in the first case NaOH dissociates and CaO from calcium hydroxide after addition of water.

 

3) Explain the following terms with examples.

a) Endothermic reaction

b) Combination reaction

c) Balanced equation

d) Displacement reaction

Ans: – a) In endothermic reaction heat is absorbed from the outside, from the reaction we can clarify that heat is absorbed i.e NH4Cl and water reaction, H2O and potassium chloride, ammonium nitrate and water reaction.

b) In a combination reaction two or more reactants react and from one substance. Example: – 2Mg + O2 = 2MgO.

c) When in a reaction where the no of atoms of reactants and products is same the reaction is called balanced reaction. Example: – 2H2 + O2 = 2H2O.

d) Fe + CuSO4 —> FeSO4 + Cu , in this reaction sulphate group get displaced from Cooper sulphate to Fe and form FeSO4 which is an displacement reaction.

 

4) Give scientific reasons.

a) When the gas formed on heating limestone is passed through freshly prepared lime water, the lime water turns milky.

Ans: – After heating limestone it form calcium oxide and carbon dioxide

CaCO3 + heat —> CaO + CO2.

And this CaO after reaction with water form calcium hydroxide and these hydroxides after reaction with CO2 the solution turns milky.

 

b) It takes time for pieces of Shahabad tile to disappear in HCl, but its powder disappears rapidly.

Ans: – When a pieces of Shahabad tile react with HCl then CO2 comes out slowly but in reaction with Shahabad CO2 comes out faster from this reaction and for this reason powder disappears rapidly.

 

c) While preparing dilute sulphuric acid from concentrated sulphuric acid in the laboratory, the concentrated sulphuric acid is added slowly to water with constant stirring.

Ans: – When sulphuric acid react with water the reaction is an exothermic reaction as huge amount of heat is produce. And for this condition slowly H2SO4 are mixed to water while preparing dilute sulphuric from concentrated sulphuric acid.

 

d) It is recommended to use air tight container for storing oil for long time.

Ans: –Oil must store in a container tightly because when it comes to contact with air it gets oxidized. And after the oxidation of oil with air it becomes rancid.

 

5) Observe the following picture a write down the chemical reaction with explanation.

Ans: – The reaction is happening at the time of rusting. In rusting iron and oxygen get reacted to each other. In this reaction Fe2+ get oxidized to Fe3+ in anode and O2 get reduce to form water.

Fe2+ —> Fe3+ ; O2 + H+ —> H2O ; Fe(3+) + H2O —> Fe2O3.H2O.

After the reaction a reddish colour layer is formed which known as corrosion.

 

6) Identify from the following reactions the reactants that undergo oxidation and reduction.

a) Fe +S —> FeS

b) 2Ag2O —> 4 Ag + O2

c) 2Mg + O2 —> 2MgO

d) NiO + H2 —> Ni + H2O.

Ans: – a) In Fe + s —> Fes reaction Fe get oxidized  and after oxidation it form ferrus sulphide or FeS.

b) 2Ag2O —> 4Ag + O2 , in this reaction oxygen removed so after reduction oxygen get removed from Ag2O .

c) 2Mg + O2 —> 2MgO , this is oxidation reaction as oxygen molecules are added in this reaction so oxygen get oxidized.

d) NiO+ H2 —> Ni + H2O ; nickel are formed after the reduction of nickel oxides as the oxygen atom reduced from the NIO and form Ni. This is a reduction reaction.

 

7)  Balance the following equation stepwise.

a) H2S2O7(l) + H2O(l) —> H2SO4(l)

b) SO2(g) + H2S(aq) —> S(s) + H2O (l)

c) Ag(s) + HCl(aq) —> AgCl + H2

d) NaOH (aq) + H2SO4(aq) —> Na2SO4(aq) + H2O(l)

Ans: –

a) H2S2O7 + H2O —> 2H2SO4.

b) SO2 + 2H2S = 3S + 2H2O .

c) 2Ag + 2HCl = 2AgCl + H2.

d) 2NaOH + H2SO4 = Na2SO4 + 2H2O.

 

8) Identify the endothermic and exothermic reaction.

a) HCl + NaOH —> NaCl + H2O + heat

b) 2KClO3(s) —> 2KCl(s) + 3O2

c) CaO + H2O —> Ca(OH)2 + heat

d) CaCO3(s) —> CaO(s) + CO2

Ans: –a) Exothermic reaction; b) Endothermic reaction; c) Exothermic reaction; d) Endothermic reaction.

 

9) Match the column in the following table.

Reactants	Products	Types of chemical reaction
BaCl2(aq) + ZnSO4	H2CO3(aq)	Displacement
2AgCl(s)	FeSO4(aq) + Cu(s)	Combination
CuSO4(aq) + Fe	BaSO4 + ZnCl2(aq)	Decomposition
H2O + CO2	2Ag + Cl2	Double Decomposition

 

Ans: –

Reactants	Products	Types of chemical reaction
BaCl2 + ZnSO4	BaSO4 + ZnCl2	Double displacement
2AgCl	2Ag + Cl2	Decomposition
CuSO4 + Fe	FeSO4 + Cu	Displacement
H2O + CO2	H2CO3	Combination

 

 

Here is your solution of Maharashtra Board Class 10 Science Part – 1 Chapter 3 Chemical Reaction And Equation

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