Chemical Reactions and Equations

1. If a substance formed in the reaction is gas, it is indicated by                                             
     A)        B)       C)       D)  
 

2. If a substance is precipitated in the reaction, it is indicated by                                           
     A)       B)       C)       D)  

 

3. Select the correct balanced chemical equation of the following                                            
     A) N₂ + 3 H₂   2 NH₃           B) H₂ + Cl₂   HCl
     C) AgCl   Ag + Cl₂              D) CuO + H₂   2 Cu + H₂O
 

4. Select the incorrect balanced chemical equation of the following.                                       
     A) 4 NH₃ + Cl₂   N₂H₄ + 2 NH₄Cl     B) NH₃ + 3 Cl₂  NCl₃ + 3 HCl
    C) 8 NH₃ + 3 Cl₂   6 NH₄Cl + N₂       D) 2 NH₃ + 3 Cl₂ 

 2 NCl₃ + 3 HCl
 

5. CaO reacts with water to form                                                                                                
     A) CaCO₃      B) CaOH      C) Ca(OH)₂      D) CaCl₂
 

6. A white precipitate will be formed if we add common salt solution to                               
     A) Ba(NO₃)₂Solution           B) KNO₃ Solution
     C) AgNO₃ Solution              D) Mg(NO₃)₂ Solution
 

7. AgNO₃ + NaCl                                                                                                                   
     A) AgCl + NaNO₃           B) AgCl + Na₂NO₂
     C) AgCl₂ + NaNO₂         D) Ag₂Cl + NaNO₃
 

8. After white washing the walls appear to be white due to the formation a layer of ..... This layer is formed by the reaction Calcium hydroxide solution (lime water) with CO₂ in air          
     A) Gypsum                 B) Limestone     C) Plaster of Paris      D) Bleaching powder
 

9. "Water added to quick lime" this reaction is                                                                        
     A) Photochemical reaction      B) Photo reaction
     C) Exothermic reaction           D) Endothermic reaction
 

10. During a chemical change, the following change takes place                                              
     A) Products are changed into reactants
     B) Reactants give the products
     C) Atoms of one element change into atoms of another element
     D) Properties of products are almost similar to those of the reactants.
 

11. One of the following does not take place during a chemical reaction                                 
     A) Atoms rearrange to give the products
     B) New substances form, having different properties
     C) Atoms of one element change into atoms of another element
     D) Old bonds break and new bonds form
 

12. Gram Molar Volume is                                                                                                            
     A) 2.24 l           B) 2.24 ml              C) 22.4 l             D) 22.4 ml
 

13. Avagadro's number is                                                                                                               
     A) 6 × 10¹⁰        B) 6 × 10²⁴           C) 6.02 × 10²³        D) 6.02 × 10³⁴

14. Nitrogen combines with Hydrogen to give Ammonia, the balanced equation is              
     A) N₂ + H₂   NH₃           B) N + H₃   NH₃
     C) N₂ + 3 H   NH₃          D) N₂ + 3 H₂   2 NH₃
 

15. The substances that are present on right side of a chemical equation are called            
     A) reactants        B) products        C) oxidants        D) reductants
 

16. The arrow mark between the products and reactants of a chemical equation shows of the reaction                                                                                                               
     A) Combination      B) Decomposition     C) Displacement      D) Direction
 

17. When 3 grams of Mg reacts with excess of dil HCl, the weight of H₂ liberated is (at. wt of Mg = 24)                                                                                                              
     A) 0.2 gram      B) 0.25 gram     C) 0.5 gram      D) 1 gram
 

18. 3 gram of Carbon is completely burnt in large excess of Oxygen, the weight of CO₂ formed is                                                                                                                         
      (At. wt of O = 16, At. wt of C = 12)
     A) 7 gram      B) 11 gram      C) 14 gram      D) 17 gram
 

19. Calculate the amount of Aluminium required to the reduction of Fe₂O₃ to get 1120 kg of Iron (At.wt of Al = 27, At.wt of Fe = 56)                                                             
     A) 54 kg      B) 104 kg      C) 540 kg      D) 560 kg
 

20. Calculate the mass of Hydrogen liberated when 230 grams of Sodium reacts with excess of water (At. wt of Na = 23)                                                                                
     A) 1 gram      B) 23 gram      C) 10 gram      D) 5 gram

21. Calculate the volume of Hydrogen liberated when 230 gram of Sodium reacts with excess of water at STP (At.wt of Na = 23)                                                                                       
     A) 22.4 litre      B) 44.8 litre     C) 112 Litre      D) 224 Litre

22. Calculate the number of molecules of Hydrogen liberated when 230 gram of Sodium reacts with excess of water (At.wt. of Na = 23)                                                                         
     A) 6.02 × 10²³      B) 6.02 × 10²⁴     C) 3.01 × 10²³      D) 3.01 × 10²⁴

23. In the equation CH₄ + 2 O₂CO₂ + 2 H₂O the amount of Oxygen needed to burn 4 gram of Methane completely is                                                                                              
     A) 4 gram      B) 8 gram      C) 16 gram      D) 32 gram

24. While writing chemical equation, if the reaction is exothermic the energy released is expressed by the sign                                                                                                                
     A) +      B) −      C) ×      D) ÷

25. While writing chemical equation if the reaction is endothermic the energy absorbed is expressed by the sign                                                                                                                   
     A) +      B) −      C) ×      D) ÷

26. N₂ + 3 H₂ 2 NH₃ + 22.4 k.cal; is an example for ....... reaction.                           
     A) Exothermic      B) Endothermic      C) Neutral      D) None

27. N₂ + O₂ 2 NO - 43.2 k.cals is an example for ........ reactions.                                
     A) Exothermic      B) Endothermic      C) Neutral      D) None

28. Downward arrow ( ) in a chemical equation indicates                                                        
     A) Precipitate      B) Direction      C) Gas      D) None

29. Barium chloride solution and Sodium sulphate solution respectively appear as ....        
     A) Both colourless                B) White and colourless
     C) Colourless and white      D) Green and yellow

30. On mixing aqueous solutions of Barium chloride and Sodium sulphate we observe that.......                                   
     A) A White precipitate is formed immediately     
     B) A transparent solution is formed
     C) A colourless gas is evolved
     D) A pungent smelling gas evolves with brisk effervescence.

31. Choose the balanced equation                                                                                                 
     A) 2 Zn + H₂SO₄  2 ZnSO₄ + H₂       B) AgNO₃ + 2 NaCl  AgCl₂ + 2 NaNO₃
     C) 2 Na + 2 H₂O 

 2 NaOH + H₂          D) C₃H₈ + 6 O₂  3 CO₂ + 4 H₂O

32. 2 NaCl + 2 H₂O  ....... + Cl₂ + H₂                                                                                  
     A) Na₂H₂      B) Na₂OH      C) 2 NaOH      D) Na(OH)₂

33. Zn + 2 AgNO₃  ....... + 2 Ag ( )
     A) Zn (NO₃)₄      B) ZnNO₃      C) 2 ZnNO₃      D) Zn(NO₃)₂
Ans: 30-A;   31-C;   32-C;   33-D;

34. If the chemical equation K₂Cr₂O₇  K₂CrO₄ + Cr₂O₃ + O₂ is balanced then        
     A) 2 K₂Cr₂O₇  2 K₂CrO₄ + 2 Cr₂O₃ + 2 O₂     
     B) 4 K₂Cr₂O₇  4 K₂CrO₄ + Cr₂O₃ + 3 O₂
     C) 2 K₂Cr₂O₇  2 K₂CrO₄ + 3 Cr₂O₃ + 3 O₂
     D) 4 K₂Cr₂O₇  4 K₂CrO₄ + 2 Cr₂O₃ + 3 O₂

35. Select the correct balanced chemical equation of the following                                         
     A) 2 NaOH + 2 Zn  Na₂ZnO₂ + H₂
     B) 2 Na₂CO₃ + 2 HCl   2 NaCl + H₂O + CO₂
     C) 2 HCl + Zn  ZnCl₂ + H₂
     D) C₃H₈ + 2 O₂  3 CO₂ + 4 H₂O
 

36. Chemical formula of lime stone :
A) CaCO₃
B) CA(OH)₂
C) CaO
D) Ca(HCO₃)₂
 

37. NaCl + AgNO₃ → AgCl↓ + NaNO₃. This reaction is an example of ............
A) Chemical combination
B) Chemical decomposition
C) Chemical displacement
D) Chemical double displacement
 

38. X Na + Y H₂O → 2 NaOH + H₂. In this balanced equation X, Y values are .......
A) 1, 1
B) 2, 1
C) 1, 2
D) 2, 2
 

39. At STP any gas occupies the volume is
A) 22.4 ml
B) 22.4 Lit
C) 22.4 gm
D) 22.4 mg
 

40. Which vitamins are adding to spoilage of food can be prevented?
A) C and E
B) A and B
C) B and K
D) C and K
 

41. Which of the following is not a redox reaction?
A) Mg + Cl₂ → MgCl₂
B) CuO + H₂ → Cu + H₂O
C) AgNO₃ + NaCl → AgCl + NaNO₃
D) MnO₂ + 4 HCl → MnCl₂ + 2 H₂O + Cl₂
 

42. Which gas used for prevent the chips from getting oxidised?
A) Hydrogen
B) Oxygen
C) Carbondioxide
D) Nitrogen
 

43. X Pb(NO₃)₂ → Y PbO + Z NO₂ + O₂. In this reaction X, Y and Z values are
A) 1, 1, 2
B) 1, 2, 4
C) 2, 2, 4
D) 4, 2, 3
 

44. Which is the oxidative deterioration of metal?
A) Layer
B) Combustion
C) Rancidity
D) Corrosion

45. 2 AgBr  2Ag + Br₂. This reaction example of ....
A) combination
B) displacement
C) double displacement
D) photo chemical reaction

46. Burning of Magnesium ribbon is a .......... type of reaction.
A) Combination
B) Decomposition
C) Displacement
D) Double Decomposition

47. The gas contained in LPG cylinders used in our house is ............
A) Methane
B) Ethane
C) Butane
D) Pentane

48. Gram Molar volume indicates ............
A) 2.24 l
B) 22.4 l
C) 2.42 l
D) 24.2 l

49. In electrolysis of water, gas evolved at cathode is .........
A) Hydrogen
B) Oxygen
C) Methane
D) None of these
 

Ans: 1-D;    2-C;   3-A;   4-D;    5-C;   6-C;   7-A;   8-B;   9-C;   10-B;   11-C;   12-C;   13-C;    14-D;   15-B;    16-D;   17-B;   18-B;   19-C;   20-C; 21-C;   22-D;   23-C;  24-A;   25-B;   26-A;   27-B;   28-A;   29-A;  34-D;   35-C;  36-A;   37-B;   38-C;   39-A;   40-D; 41-D;   42-C;   43-D;   44-C;    45-A;   46-B;   47-D;   48-D;   49-A.