, Name of the Chapter : Chemical Reactions and Equations
CASE BASED MCQs
I. Clean a magnesium ribbon about 2 cm long by rubbing it with sandpaper. Hold it with a
pair of tongs. Burn it using a spirit lamp or burner and collect the ash so formed in a
watch-glass.
1. Magnesium ribbon is rubbed before burning because it has a coating of
A. basic magnesium carbonate C. basic magnesium sulphide
B. basic magnesium oxide D. basic magnesium chloride
2. What is the colour of magnesium ribbon?
A. White C. Grey
B. Black D. Yellow
3. What is the chemical name of the powder obtained in the activity?
A. magnesium carbonate C. magnesium sulphide
B. magnesium oxide D. magnesium chloride
4. Which compound is formed when the powder obtained reacts with water?
A. Magnesium sulphate C. Magnesium carbonate
B. Magnesium oxide D. Magnesium hydroxide
II. Take a plastic mug, drill two holes at its base and insert carbon electrodes. Connect
these electrodes to a 6 volt battery. Fill the mug with water such that the electrodes are
immersed. Add a few drops of dilute sulphuric acid to the water. Take two test tubes
, filled with water and invert them over the two carbon electrodes. Switch on the current
and leave the apparatus undisturbed for some time.
1. What is the ratio in which hydrogen and oxygen are present in water by
volume?
A. 1:2 C. 2:1
B. 1:1 D. 1:8
2. Which electrodes are used in this activity?
A. Graphite C. Copper
B. Diamond D. Coke
3. Where is hydrogen gas collected?
A. Anode
B. Cathode
C. At both electrodes
D. Hydrogen gas is not evolved in this activity
4. Which of the following is an endothermic process?
A. Dilution of sulphuric acid
B. Condensation of water vapours
C. Respiration in human beings
D. Electrolysis
III. Take about 2 g ferrous sulphate crystals in a dry boiling tube. Heat the boiling tube over
the flame of a burner or spirit lamp. In this reaction you can observe that a single
reactant breaks down to give simpler products. This is a decomposition reaction.
Ferrous sulphate crystals (FeSO4, 7H2O) lose water when heated and the colour of the
crystals changes. It then decomposes to ferric oxide (Fe2O3), sulphur dioxide (SO2)
and sulphur trioxide (SO3). Ferric oxide is a solid, while SO2 and SO3 are gases.
, 1.What can we observe in this activity?
A. Water vapor is evolved
B. Change in colour
C. Smell of burning sulphur
D. All of the above.
2.What is the colour of iron oxide?
A.Brown B.Grey
C.Yellow D.White
3.What compound is formed when sulphur dioxide is passed through water?
A.Sulphuric acid B.Sulphurous acid
C.Hydrogen Sulphide D.Sulphur trioxide
IV: Read the following and answer the questions
The double displacement reaction is a type of chemical reaction. where two compounds
react and the cation and anion of the two reactants 6 places forming 2 new products. The
ionic compounds considered as reactants are water soluble. One of the products is formed
as a precipitate or as a gas which is water soluble.
1. The reaction between lead nitrate and potassium iodide is an example of.
A) Combination reaction B) Decomposition Reaction
C) Displacement reaction D) Double displacement reaction.
2.What was the color of the precipitate formed when Lead nitrate reacts with Potassium
iodide ?
A) Blue B) Red C) Yellow D) Orange
3. Which metallic spoon can be used to stir Lead nitrate solution ?
A)Sodium B)Silver C) Iron D) Aluminum
CASE BASED MCQs
I. Clean a magnesium ribbon about 2 cm long by rubbing it with sandpaper. Hold it with a
pair of tongs. Burn it using a spirit lamp or burner and collect the ash so formed in a
watch-glass.
1. Magnesium ribbon is rubbed before burning because it has a coating of
A. basic magnesium carbonate C. basic magnesium sulphide
B. basic magnesium oxide D. basic magnesium chloride
2. What is the colour of magnesium ribbon?
A. White C. Grey
B. Black D. Yellow
3. What is the chemical name of the powder obtained in the activity?
A. magnesium carbonate C. magnesium sulphide
B. magnesium oxide D. magnesium chloride
4. Which compound is formed when the powder obtained reacts with water?
A. Magnesium sulphate C. Magnesium carbonate
B. Magnesium oxide D. Magnesium hydroxide
II. Take a plastic mug, drill two holes at its base and insert carbon electrodes. Connect
these electrodes to a 6 volt battery. Fill the mug with water such that the electrodes are
immersed. Add a few drops of dilute sulphuric acid to the water. Take two test tubes
, filled with water and invert them over the two carbon electrodes. Switch on the current
and leave the apparatus undisturbed for some time.
1. What is the ratio in which hydrogen and oxygen are present in water by
volume?
A. 1:2 C. 2:1
B. 1:1 D. 1:8
2. Which electrodes are used in this activity?
A. Graphite C. Copper
B. Diamond D. Coke
3. Where is hydrogen gas collected?
A. Anode
B. Cathode
C. At both electrodes
D. Hydrogen gas is not evolved in this activity
4. Which of the following is an endothermic process?
A. Dilution of sulphuric acid
B. Condensation of water vapours
C. Respiration in human beings
D. Electrolysis
III. Take about 2 g ferrous sulphate crystals in a dry boiling tube. Heat the boiling tube over
the flame of a burner or spirit lamp. In this reaction you can observe that a single
reactant breaks down to give simpler products. This is a decomposition reaction.
Ferrous sulphate crystals (FeSO4, 7H2O) lose water when heated and the colour of the
crystals changes. It then decomposes to ferric oxide (Fe2O3), sulphur dioxide (SO2)
and sulphur trioxide (SO3). Ferric oxide is a solid, while SO2 and SO3 are gases.
, 1.What can we observe in this activity?
A. Water vapor is evolved
B. Change in colour
C. Smell of burning sulphur
D. All of the above.
2.What is the colour of iron oxide?
A.Brown B.Grey
C.Yellow D.White
3.What compound is formed when sulphur dioxide is passed through water?
A.Sulphuric acid B.Sulphurous acid
C.Hydrogen Sulphide D.Sulphur trioxide
IV: Read the following and answer the questions
The double displacement reaction is a type of chemical reaction. where two compounds
react and the cation and anion of the two reactants 6 places forming 2 new products. The
ionic compounds considered as reactants are water soluble. One of the products is formed
as a precipitate or as a gas which is water soluble.
1. The reaction between lead nitrate and potassium iodide is an example of.
A) Combination reaction B) Decomposition Reaction
C) Displacement reaction D) Double displacement reaction.
2.What was the color of the precipitate formed when Lead nitrate reacts with Potassium
iodide ?
A) Blue B) Red C) Yellow D) Orange
3. Which metallic spoon can be used to stir Lead nitrate solution ?
A)Sodium B)Silver C) Iron D) Aluminum
