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Lakhmir Singh & Manjit Kaur Test: Chemical Reactions and Equations


15 Questions MCQ Test Science Class 10 | Lakhmir Singh & Manjit Kaur Test: Chemical Reactions and Equations


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This mock test of Lakhmir Singh & Manjit Kaur Test: Chemical Reactions and Equations for Class 10 helps you for every Class 10 entrance exam. This contains 15 Multiple Choice Questions for Class 10 Lakhmir Singh & Manjit Kaur Test: Chemical Reactions and Equations (mcq) to study with solutions a complete question bank. The solved questions answers in this Lakhmir Singh & Manjit Kaur Test: Chemical Reactions and Equations quiz give you a good mix of easy questions and tough questions. Class 10 students definitely take this Lakhmir Singh & Manjit Kaur Test: Chemical Reactions and Equations exercise for a better result in the exam. You can find other Lakhmir Singh & Manjit Kaur Test: Chemical Reactions and Equations extra questions, long questions & short questions for Class 10 on EduRev as well by searching above.
QUESTION: 1

H2SO4 + 2NaOH → Na2SO4 + 2H2O
Above equation is a:

(i) neutralization reaction

(ii) double displacement reaction

(iii) decomposition reaction

(iv) addition reaction

Solution:
  • A neutralization reaction can be defined as a chemical reaction in which an acid and base quantitatively react together to form salt and water as products. In a neutralization reaction, there is a combination of H+ ions and OH– ions that form water.

  • A double displacement reaction is a type of reaction in which two reactants exchange ions to form two new compounds. Double displacement reactions typically result in the formation of a product that is a precipitate. 
    Double displacement reactions take the form: AB + CD → AD + CB

QUESTION: 2

Identify the following reactions as endothermic or exothermic,

(i) 2NaHCO3 + energy → Na2CO3 + H2O + CO2

(ii) 2Mg + O2 → 2MgO + energy

Solution:
  • Reaction with the absorption of energy is called an endothermic reaction.
    In reaction (i) Sodium Bicarbonate needs the energy to form sodium carbonate, water and carbon dioxide. 
    Hence it is an endothermic reaction.
  • Reaction with the release of energy is called an exothermic reaction.
    In the reaction (ii) on the burning of magnesium wire, magnesium oxide is formed by the release of energy in the form of heat and light.
    Hence it is an exothermic reaction.

 

 

QUESTION: 3

Correct balanced equation from the following reactions is:

Solution: On balancing the atoms of all the elements, we will get the following chemical equation-

QUESTION: 4

In a double displacement reaction?
Solution: Those reactions in which two compounds react by an exchange of ions to form two new compounds are called double displacement reactions.

QUESTION: 5

The reaction, 3MnO2(s) + 4AI(s) → 3Mn(l) + 2Al2O5(s) + Heat is an example of:
Solution: 3MnO2(s) + 4AI(s) → 3Mn(l) + 2Al2O5(s)

Aluminium being more reactive displaces the manganese metal and forms a new compound. Hence it is a displacement reaction.

The heat is also released along with the formation of products, hence it is an exothermic reaction.

QUESTION: 6

The reaction Pb(NO3)2 + 2NaI → 2NaNO3 + PbI2 ↓ is classified as
Solution: In this reaction, two new substances lead iodide, and sodium nitrate are formed by an interchange of radicals in lead nitrate and sodium iodide.

QUESTION: 7

Which of the statements about the reaction below are incorrect?
2PbO(s) + C(s) → 2Pb(s) + CO2 (g)

(i) Lead is getting reduced.
(ii) Carbon dioxide is getting oxidised.
(iii) Carbon is getting oxidised.
(iv) Lead oxide is getting reduced.
Solution:

In the above reaction, lead oxide is getting converted to lead and carbon is getting converted to carbon dioxide. Lead oxide is losing oxygen whereas carbon is gaining oxygen. Loss of oxygen is known as reduction while gaining oxygen is called oxidation. Hence, Lead oxide is getting reduced and carbon is getting reduced. Thus statements (iii) and (iv) are correct whereas statements (i) and (ii) are incorrect.

QUESTION: 8

Fe2O3 + 2Al → Al2O3 + 2Fe
The above reaction is an example of a:
Solution:

In the given reaction, Ferric oxide is getting converted to Iron while aluminium is getting oxidized to aluminium oxide. Thus, iron is going from a combined state to a free state whereas aluminium is going from a free state to the combined state. Such a reaction is called displacement reaction as in displacement reactions, the more reactive metal (Al in this case) displaces the less reactive metal (Fe in this case) from its compound.

QUESTION: 9

What happens when dilute hydrochloric acid is added to iron fillings? Tick the correct answer.​
Solution:

When metals react with acids, H2 gas is evolved along with the formation of the respective salt of metal.
Fe(s) + 2HCl(aq) → FeCl2(s) + H2(g) ↑

QUESTION: 10

Two different atoms or groups of atoms (ions) are exchanged in ______ reactions.
Solution: A double displacement reaction is a reaction where part of one reactant is replaced by part of another reactant. AB + CD → AD + CB

QUESTION: 11

When lead nitrate is heated, it breaks down into lead monoxide, nitrogen dioxide and oxygen.

2Pb(NO3)2 → 2PbO + 4NO2 + O2

The reaction is an example of:
Solution:

A decomposition reaction is a reaction in which a compound breaks down into two or more simpler substances. The general form of a decomposition reaction is AB→A+B. Most decomposition reactions require an input of energy in the form of heat, light, or electricity.

QUESTION: 12

Thermal decomposition of a substance is brought about with the help of
Solution: Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition.

QUESTION: 13

Aluminium can displace Zinc metal from the aqueous solution of zinc sulphate because of ______.
Solution: In the displacement series of metals for displacement reactions, aluminium is above the zinc metal signifying that aluminium is more reactive than zinc. Therefore, aluminium can displace Zn metal from the aqueous solution of zinc sulphate.

QUESTION: 14

The reaction Pb(NO3)2 + 2NaI → 2NaNO3 + Pbl2 ↓ is classified as
Solution:

In this reaction, two new substances lead iodide, and sodium nitrate are formed by an interchange of radicals in lead nitrate and sodium iodide.

 

 

QUESTION: 15

A piece of granulated zinc was dropped into a copper sulphate solution. After some time, the colour of the solution changed from:
Solution: When a piece of granulated zinc was dropped into the copper sulphate solution, the colour of the solution changes from blue to colourless as the following reaction takes place

Zn + CuSO4 → ZnSO4 + Cu blue colourless.

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