RBSE Class 10 Science Chemistry Chapter 1 Chemical Reactions and Equations MCQs (Objectives) are very important for students preparing for Board Exams. These MCQS have been prepared on the basis of important topics of chemical reactions and equations.
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In this post, you will find high- quality,
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syllabus.
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Chemical Reactions and Equations Objectives with Answers
Multiple Choice Questions
Put (√) mark against correct answer:
1.Mg+O2→MgO is a
(a) Skeletal equation
(b) balanced chemical equation
(c) Word equation
(d) all the above
Correct answer – (a)
Explanation-
In the above reaction atoms of reactants and products are not balanced at both
left and right side so it is called skeletal equation.
2.The balanced
chemical equation in the following is
(a) 2Fe+3H2O→Fe2O3+H2
(b) 2Fe+H2O→Fe2O3+H2
(c) 2Fe+3H2O→Fe2O3+3H2
(d) 2Fe+H2O→Fe2O3+3H2
Correct answer – (c)
Explanation- in the option (c ) No. of atoms of reactants
and products are balanced so this is the correct answer.
3.Symbol (↑)is used to
represent
(a) Aqueous state
(b) gaseous state
(c) Liquid state
(d) solid state
Correct answer – (b)
Explanation- all gases go upward so an up-arrow (↑) is
used to represent gaseous state.
4. Burning of coal is a / an
(a) Exothermic reaction
(b)Oxidation reaction
(c) Combination reaction
(d) All the above
Correct answer – (d)
Explanation- In the above reaction, heat is produced so
it is an exothermic reaction. Coal ( C) combines with Oxygen so it is an
oxidation reaction and combination
reaction.
5. 2KCl →2KCl +3O2is
a
(a) Isomerization reaction
(b)Displacement reaction
(c) Combination reaction
(d)Decomposition reaction
Correct answer – (d)
Explanation- In the above reaction, KCl3
breaks down into KCl and O2 in the presence of Heat so it is
decomposition reaction.
6. 2H2 + O2→2H2O
is a
(a) Isomerization reaction
(b) Displacement reaction
(c) Combination reaction
(d) Decomposition reaction
Correct answer – (c)
Explanation- In the above reaction, Hydrogen combines
with Oxygen to produced water so it is Combination reaction.
7.
(a) Combination equation
(b) Decomposition reaction
(c) Isomerization reaction
(d) Displacement reaction
Correct answer – (d)
Explanation- In the above reaction, Fe displaces Hydrogen
from water and Fe2O3.
8. Metal more reactive than
copper, is
(a) Fe
(b) Zn
(c) Pb
(d) All the above
Correct answer – (d)
Explanation- According to reactivity series Fe, Zn, Pb
are more reactive than copper.
9. When zinc pieces are
added to dilute sulphuric acid, a.................... reaction takes place.
(a) Displacement
(b) Double displacement
(c) Decomposition
(d) Combination
Correct answer – (d)
Explanation- According to reactivity series Fe, Zn, Pb
are more reactive than copper.
10. When barium chloride is
added to sodium sulphate solution, reaction takes place.
(a) Displacement
(b)Double displacement
(c) Combination
(d)Decomposition
Correct answer – (d)
Explanation- According to reactivity series Fe, Zn, Pb
are more reactive than copper.
11. The reaction in which
heat is absorbed is called
(a) Isomerization reaction
(b) Endothermic reaction
(c) isothermic reaction
(d) Exothermic reaction
Correct answer – (b)
Explanation- In endothermic reaction heat is absorbed
during chemical reaction.
12. The reaction in which
heat is produced is called
(a) isomerisation reaction
(b) Endothermic reaction
(c) Isothermic reaction
(d)Exothermic reaction
Correct answer – (d)
Explanation- In the exothermic reaction, heat is liberated.
13. For decomposition
reaction, energy is required in the form of
(a) Heat
(b)Light
(c) Electricity
(d)All the above
Correct answer – (d)
Explanation
– In the decomposition reaction energy is required and heat, light and
electricity are the forms of energy.
14. A reaction in which a
substance combines with oxygen, is called as
(a) Endothermic reaction
(b) Exothermic reaction
(c) Oxidation reaction
(d) Reduction reaction
Correct answer – (c)
Explanation
– when Oxygen is added to a substance, it is called and Oxidation reaction.
15. A reaction in which a
substance combine with hydrogen, is called as
(a) Endothermic reaction
(b)Exothermic reaction
(c)Oxidation reaction
(d)Reduction reaction
Correct answer – (d)
Explanation
– When a substance combines with hydrogen, it receives electron and get
reduced.
16.On passing a gas, lime
water becomes milky, the passed gas is
(a) Argon
(b) Carbon monoxide
(c) Carbon
dioxide
(d) Hydrogen
Correct answer – (c)
17. Rancidity occurs when
fats and oils are
(a) Oxidation reaction
(b) Reduction reaction
(c) Decomposition
reaction
(d) Displacement reaction
Correct answer – (d)
Explanation
– Fats and oils react with atmospheric
oxygen , they become rancid and it is an Oxidation reaction.
18.The example of a physical
change is
(a)milk is left at room
temperature is summers
(b)an iron tawa is heated
(c)iron tawa is left exposed
to humid air
(d)food is cooked
Correct answer – (b)
Explanation
– because on heating iron tawa or other
iron articles are heated , there is no chemical change occurs so it an example
of physical change.
19.Which of the following is
a double displacement reaction
(a) C+O2 →CO2
(b)CuSO4 +Fe
→FeSO4 +Cu
(c) CH4 +2O2
→CO2 +2H2O
(d) Na2SO4+baCl2
→BasO4+2NaCl
Correct answer – (d)
20.Which of the following is / are exothermic processes
(i) Sublimation of ammonium chloride
(ii) Quick lime is added to water
(iii) Evaporation of water
(iv)Dilution of an acid
(a) (i) and (ii)
(b) (ii)
and (iii)
(c) (iii) and (iv)
(d) (ii)
and (iv)
Correct answer – (d)
Explanation
– when quick lime is added to water ,
heat is produced and heat is also liberated when an acid is diluted.
21.Fe2O3 + 2Al →Al2O3+2Fe is a
(i) combination reaction
(ii) displacement reaction
(iii) redox reaction
(iv) double displacement reaction
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (ii)
and (iv)
Correct answer – (b)
22. Silver bromide, on
exposure to sunlight turns grey due to
(a) Formation of silver by its decomposition
(b) Oxidation of silver
bromide
(c) Sublimation of silver
bromide
(d) Decomposition of bromine
gas from silver bromide
Correct answer – (a)
Explanation
– when Silver bromide (AgBr) is kept in sunlight , it gets decomposed into
silver and bromine
Sunlight
AgBr
→Ag +Br
23.Water on electrolysis
decomposes to hydrogen and oxygen. The mole ratio of hydrogen and oxygen is
(a) 1:2
(b) 1:1
(c) 2:1
(d) 4:1
Correct answer – (c)
24.A dilute ferrous sulphate
solution is added to acidified permanganate solution. The light purple colour
of the solution fades and finally disappears. It is due to
(a) KMnO4 is an oxidising agent and oxidation of FeSO4
occurs
(b) Colour appears due to
dilution and no reaction takes place
(c) FeSO4 acts as an oxidising
agent
(d) KMnO4 is an
unstable compound and decomposes to a colourless compound.
Correct answer – (a)
25. Which of the following
is (are) an endothermic reaction (s)
(a) Sublimation of camphor
(b) Evaporation of water
(c) Condensation of water
vapour
(d) Dilution of acid
Correct answer – (a)
26. Which of the following
gases can be used for storage of fresh sample of an oil for a long time
(a) Nitrogen and oxygen
(b) CO2 and
helium
(c) CO2 and
oxygen
(d) Nitrogen and helium
Correct answer – (d)
Explanation
– Nitrogen and Helium both are inactive gases so they stop the Oxidation
process of any food stuff containing oil.
27.100 mL of water was taken
in beakers A, B and C. A small amount of CuSO4, NaOH and NaCI were added to beaker A, B and C
respectively. The temperature of beaker A and B increased where in beaker C
decreases. The correct statement (s) is / are
(i) In beaker C exothermic process has occurred
(ii) In beakers A and B,
exothermic process has occurred
(iii) In beakers A and B
endothermic process has occurred
(iv) In beaker C endothermic
process has occurred
(a) (i) and (ii)
(b) (ii)
and (iii)
(c) (iii) and (iv)
(d) (ii)
and (iv)
Correct answer – (d)
28. Chemical formula of rust
is
(a) Fe2O3
(b) FeCO3
(c) Fe2O3.xH2O
(d) FeCO3.xH2O
Correct answer – (c)
29. For rusting of iron, the
essential requirement is
(a) Air
(b) Water
(c) Open
surface of metal
(d) All the above
Correct answer – (d)
30. Rusting is a / an
(a) Oxidation reaction
(b) Reduction reaction
(c) Decomposed
(d)None of the above
Correct answer – (a)
Explanation- During the rusting, iron combines with atmospheric oxygen so it
an oxidation reaction.
31.A student while heating
solid lead nitrate taken in a test tube would observe
(a). Yellow residue of PbO
(b) White residue of PbO2
(c) Green residue of NO2
(d) Brown residue of NO
Correct answer – (d)
32.chemical changes
are…………………
(a) Always accompanied with
exchange of light
(b) Temporary ,
reversible and a new substance is
produced
(c ) Permanent , irreversible and a new
substance is produced
(d) Never accompanied with
exchange of light and heat energy
Correct answer – (c)
33.Magnesium 6+ Oxygen
→Magnesium oxide is an example of
(a) Double displacement
reaction
(b) Simple displacement
reaction
(c) Combination reaction
(d) Decomposition reaction
Correct answer – (c)
34.Which of the following
will be required to identify the gas evolved when dilute hydrochloride acid
reacts with Zinc metal
(a) red litmus
(b) blue litmus
(c) a burning splinter
(d) lime water
Correct answer – ( c)
Explanation
– In the above reaction Hydrogen gas evolves and it is an inflammable gas so with
the help of a burning splinter, it can be identified.
35. Which among the following
is not a physical change?
(a) Liquification of gases
into liquids
(b) Vaporization of liquids
into gases
(c) Melting of solids to
liquids
(d) Decay of matter
Correct answer – (d)
Explanation
– After decay of matter, new substances are formed and it is an irreversible
process so it not a physical change.
36. Breaking of lead bromide
into lead and bromine is an example of …….
(a) Displacement reaction
(b) Decomposition reaction
(c) Combination reaction
(d) Neutralization reaction
Correct answer – (b)
37. NaCl +AgNO3→AgCl+ NaNO3 is
an example of ……
(a) Decomposition reaction
(b) Double displacement
reaction
(c) Combination reaction
(d) Displacement reaction
Correct answer- (a)
38.The main
cause of rancidity in food items is…..
(a) Antioxidants
(b) Oxidation of the fats
present in food items
(c) Bacteria
(d) Proteins present in the
food items
Correct answer- (b)
39.Rancidity
can be prevented by
(a) Storing food away from
light
(b) Adding antioxidants
(c) Keeping food in
refrigerator
(d) All of these
Correct answer- (d)
40. What is
the chemical name of slaked lime?
(a) Calcium oxide
(b) Calcium Hydroxide
(c) Calcium dioxide
(d) Carbon mono oxide
Correct answer- (b)
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