Class 10 Science chapter - 1 Chemical equations and reaction (part -1)

Chemical equations and reaction

MCQ (Multiple Choice Questions)

1. Which of the following reactions involves the combination of two elements :-
a)CaO + CO2 -> CaCO3
b)4Na + O2 -> 2Na2O
c)SO2 +(1/2)O2 -> SO3
d)NH3 + HCI -> NH4CI

2.When hydrogen sulphide gas is passed through a blue solution of copper sulphate, a black precipitate of copper sulphate is obtained and the sulphuric acid so formed remains in the solution. The reaction is an example of :-
a)A combination reaction
b)A displacement reaction
c)A decomposition reaction
d)A double decomposition reaction 

 3.What happens when copper rod is dipped in iron sulphate solution :-
a)Copper displaces iron
b)Blue color of copper sulphate solution is obtained
c)No reaction takes place
d)Reaction is exothermic

 4.A student added dilute HCI to a test tube containing zinc granules and made following observations :-
a)The zinc surface became dull and black
b)A gas evolved which burnt with a pop sound
c)The solution remained colorless
d)The solution becomes green in color.

5.A dilute solution of sodium carbonate was added to two test tubes one containing dilute HCI (a) and the other containing dilute NaOH (b). the correct observation was :-
a)A brown colored gas liberated in test tube A
b)A brown colored gas liberated in test tube B
c)A colorless gas liberated in test tube A
d)A colorless gas liberated in test tube B

6.A balanced chemical equation is in accordance with
a)Avogadro’s law
b)Law of multiple proportion
c)Law of conservation of mass
d)Law of gaseous volumes

7.The equation
Cu + xHNO3 -> Cu(NO3)2 + yNO2 + 2H2O
The values of x and y are
a)3 and 5
b)8 and 6
c)4 and 2
d)7 and 1

8.Zn + H2SO4(dil) ->ZnSO4 + H2 Above reaction is
a)Decomposition reaction
b)Single displacement reaction
c)Combination reaction
d)Synthesis reaction

9.The reaction in which two compounds exchange their ions to form two new compounds is
a)A displacement reaction
b)A decomposition reaction
c)An isomerization reaction
d)A double displacement reaction

10.When the gases sulphur dioxide and hydrogen sulphide mix in the presence of water, the reaction is
SO2 + 2H2S -> 2H2O + 3S. here hydrogen sulphide is acting as
a)An oxidizing agent
b)A reducing agent
c)A dehydrating agent
d)A catalyst

11.CuO + H2 ->H2O + Cu, reaction is an example of
a)Redox reaction
b)Synthesis reaction
c)Neutralization
d)Analysis reaction

12.A substance which oxidized itself and reduces other is known as
a)Oxidizing agent
b)Reducing agent
c)Both of these
d)None of these

13.A redox reaction is one in which
a)Both the substance are reduced
b)Both the substance are oxidized
c)An acid is neutralized by the base
d)One substance is oxidized while the other is reduced

14.In the following equation:
Na2CO3 + xHCI -> 2NaCI +CO2 + H2O, the value of x is
a)1          b)2      c)3             d)4

15.In the equation, NaOH + HNO3 -> NaNO3 + H2O nitric acid is acting as
a)An oxidizing agent
b)An acid
c)A nitrating agent
d)A dehydrating agent

16.Fe2O3+  2Al   ->   AI2O3 + 2Fe
The above reaction is an example of a
a)Combination reaction
b)Double displacement reaction
c)Decomposition reaction
d)Displacement reaction

17.White silver chloride in sunlight turns to
a)Grey
b)Yellow
c)Remain white
d)Red

18.Black and white photography uses
a)Decomposition of silver chloride
b)Decomposition of silver bromide
c)Both
d)None of these

19.When copper powder is heated it gets coated with
a)Black copper oxide
b)Yellow copper oxide
c)Red copper oxide
d)None of these

20.Combination of phosphorus and oxygen is an example of
a)Oxidation
b)Reduction
c)Rancidity
d)None of these

21.Rusting of an iron is an example of
a)Reduction
b)Ionization
c)Oxidation
d)Dissociation

22.Which of the following does not corrode when exposed to the atmosphere-
a)Iron
b)Copper
c)Gold
d)Silver

23.Take about 1.0g CaCO3 in a test tube. Heat it over a flame, when a colorless gas comes out. The reaction is called a
a)Decomposition reaction
b)Displacement reaction
c)Double decomposition reaction
d)Double displacement reaction

24.Hydrogen sulphide (H2S) is a strong reducing agent. Which of the following reactions shows its reducing action
a)Cd(NO3)2 + H2S -> CdS + 2HNO3
b)CuSO4 + H2S -> CuS + H2SO4
c)2FeCl3 + H2S -> 2FeCl2 + 2HCI + S
d)Pb(NO3)2 +H2S -> PbS + 2CH3COOH

25.When P reacts with caustic soda, the products are PH3 and NaH2PO2. This reaction is an example of
a)Oxidation
b)Reduction
c)Oxidation and reduction (redox)
d)Neutralization

26.2CuI-> Cu + CuI2, the reaction is
a)Redox
b)Neutralization
c)Oxidation
d)Reduction

27.When copper turning are added to silver nitrate solution, a blue coloured solution is formed after some time. It is because, copper-
a)Displaces silver from the solution
b)Forms a blue colored complex with AgNO3
c)Is oxidized to Cu2+
d)Is reduced to Cu2+

28.Zn2+ (aq) +2e -> Zn(s). this is
a)Oxidation
b)Reduction
c)Redox reaction
d)None of these
29. The pair of quick lime and slaked lime is 
a. CaO and Ca(OH)2
b. NaOH and KOH
C. CaCl2 and CaSO4
D. CaOCl2 and KCl

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