Monday, May 27, 2013

CBSE Class 10 - Science - CHEMICAL REACTIONS AND EQUATIONS (MCQs)

CHEMICAL REACTIONS AND EQUATIONS
CBSE Class 10 - Science - CHEMICAL REACTIONS AND EQUATIONS (MCQs)

MCQs

Q1: Which of the following is not a decomposition reaction?

(a) CaCO3 → CaO + CO2
(b) H2 + Cl2 → 2HCl
(c) H2CO3 → H2O + CO2
(d) 2KClO3 → 2KCl + 3O2

Q2: Which of the following is not an oxidising agent?

(a) Oxygen
(b) Conc. Sulphuric acid
(c) Chlorine
(d) Hydrogen


Q3: The oxidation reaction which produces heat and light is

(a) endothermic
(b) photochemical
(c) combustion
(d) exothermic




Q4: 2Pb(NO3)2 → 2PbO + nA + O2
       What is nA in the given reaction?

(a) 4NO
(b) 4NO2
(c) 2PbNO2
(d) NO2

Q5: A slow combustion in which glucose present in the body cells combine with oxygen to provide energy is

(a) digestion
(b) excretion
(c) respiration
(d) none of the above


Q6: The equation
      Cu + XHNO3 → Cu(NO3)2 + YNO2 + 2H2O, the value of X and Y are

(a) 3 and 1 respectively
(b) 8 and 6 respectively
(c) 4 and 2 respectively
(d) 7 and 1 respectively


Q7: When the gases sulphur dioxide and hydrogen sulphide mix in the presence of water, the reaction SO2 + 2H2S → 2H2O + 3S occurs. Here hydrogen sulphide is acting as

(a) an oxidising agent
(b) a reducing agent
(c) a dehydrating agent
(d) a catalyst


Q8: What is the chemical name of quick lime ?

(a) Calcium oxide
(b) Calcium carbonate
(c) Calcium hydroxide
(d) Carbon dioxide



Q9:Which of the following reaction will not take place?

(a) Zn + FeSO4 → ZnSO4 + Fe
(b) 2KI + Cl2 → 2KCl + I2
(c) Zn + MgSO4 → ZnSO4 + Mg
(d) Mg + CuSO4 → MgSO4 + Cu


Q10: In the reaction, 2FeCl2 + Cl2 → 2FeCl3 , chlorine may be regarded as

(a) an oxidizing agent
(b) a reducing agent
(c) a catalyst
(d) providing an inert medium


Q11: The conversion of K2Cr2O7 into Cr2(SO4)3 is a process of

(a) Oxidation
(b) Reduction
(c) Decomposition
(d) Substitution


Q12: An element, which never has a positive oxidation state in any of its compounds, is

(a) Boron
(b) Oxygen
(c) Chlorine
(d) Fluorine


Q13: Amino acid is formed by decomposition of which component of our diet?
(a) Carbohydrate
(b) Starch
(c) Protein
(d) Fat

Q14: Loss of electrons is called _________

(a) reduction
(b) oxidation
(c) can be oxidation or reduction
(d) none of these



Answers:
1: (b) H2 + Cl2 → 2HCl
2: (d) Hydrogen
3: (c) combustion
4: (b) 4NO2
5: (c) respiration
6: (c) 4 and 2 respectively
7: (b) a reducing agent
8: (a) Calcium oxide
9: (c) Zn + MgSO4 → ZnSO4 + Mg
10: (a) an oxidizing agent
11: (b) Reduction
12: (d) Fluorine
13: (c) Protein
14: (b) oxidation

7 comments:

  1. good going this site is very very......good

    ReplyDelete
  2. 4 question is wrong its option should be 4NO2

    ReplyDelete
  3. plz tell me in que.10 why chrorine is oxidising agent bcoz there r no molecules of O2

    ReplyDelete
  4. plz tell me in que.10 why chrorine is oxidising agent bcoz there r no molecules of O2

    ReplyDelete
    Replies
    1. Loss of electronegative radical or gain of +ve radical is also reduction. Thus cl2 acts as oxidising agent.

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