CBSE 10- Chemical equations-questions from previous year question papers

Chemical reaction
  1. Take 3 g of Barium Hydroxide in a test tube and now add about 2g of ammonium chloride and mix the contents with the help of a glass rod. Now touch the test tube from outside
    1. What do you feel on touching the test tube
    2. State the inference about the type of reaction occurred
    3. Write the balanced chemical equation of the reaction involved (3 marks, SA1 2016-17)
  2. Two aluminium strips were kept immersed in ferrous sulphate solution taken in a test tube. The change which was observed is :
    1. a colourless gas with the smell of burning sulphur is released
    2. Light green solution changes to blue
    3. The green solution slowly turns to brown
    4. The lower end of the test-tube becomes slightly warm (SA1 2016-17)
  3. Write balanced equations for the following reactions and identify the type of reaction in each case
    1. Silver Nitrate (aq) +Potassium Iodide (aq)—à Silver Iodide (s) + Potassium Nitrate (aq)
    2. Potassium Chlorate (s)———-àPotassium Chloride (s)+ Oxygen (g) (SA1 2015, 3 marks)
  4. A few small pieces of aluminium metal were added to ferrous sulphate solution. It was observed that:
    1. Pale green colour solution disappears and it becomes colourless
    2. Pale green colour persists
    3. Pale green colour of solution turns blue
    4. Pale green colour of solution turns red (SA1 -2015)
  5. 2Al+3CuSO4—–à 3Cu + Al2(SO4)

The type of reaction shown above and the change of colour of reaction solution to product that was observed is

  1. Combination reaction , blue to green
  2. Displacement reaction blue to colourless
  3. Decomposition reaction , blue to green
  4. Displacement reaction, blue to green
  5. Consider the following reaction

6.   Consider the following reaction

Pb(NO3)2(s)—————-à PbO(s)+NO2(g)+O2(g)

  • Write the name and colour of the NO2 gas formed
  • Balance the above chemical equation
  • Name the type of chemical reaction (SA1-2016-17, 3 marks)

7. a. Can a displacement reaction be a redox reaction? Explain with the help of examples

b. Write the type of chemical reaction in the following: (SA1 2016-17, 5 marks)

i) Reaction between an acid and a base

ii) Rusting of iron

  1. About 2.5 g of ferrous sulphate crystal were heated as show in the figure below(SA1-2016-17- 2 marks)

Chemical reactionAfter heating for one minute

  1. What change in colour of ferrous sulphate crystals would you observe
  2. On smelling the gases carefully, what would you feel?

9. A) balance the following chemical equations(SA1-2016-17- 5 marks)

  1. NaOH+H2SO4—-àNa2SO4+H2O
  2. PbO+C—àPb+CO2
  3. Fe2O3+Al—-àAl2O3+Fe+Heat

B) Write the balanced chemical equations for the following reactions

  1. Barium Chloride+Potassium sulphate—à Barium Sulphate+Potassium Chloride
  2. Zinc+ Silver nitrate–àZinc Nitrate +Silver

10. If M+BX—àMX+B and B is seen as reddish brown deposit, then M and BX are(SA1-2016-17)

  1. Iron and aluminium sulphate
  2. Iron and zinc sulphate
  3. Aluminium and copper sulphate
  4. Zinc and Iron aluminium sulphate

11. Color of Al2(SO4)3 is (SA1-2016-17)

  1. Green
  2. Yellow
  3. Blue
  4. Colourless

12. Give chemical equations for the following reactions (5 marks)

  1. Digestion of food in our body
  2. Rusting of iron
  3. Heating of manganese dioxide with aluminium powder
  4. Blue colour of copper sulphate solution disappears when iron fillings are added to it
  5. Dilute hydrochloric acid added to sodium hydroxide solution to form sodium chloride and water

 

 

 

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