A magnesium ribbon is burnt in air. A student made the following observations: i. Magnesium ribbon undergoes oxidation reaction. ii. Magnesium reacts with air to form magnesium oxide. iii. Magnesium ribbon undergoes decomposition reaction.Which of the following statements is correct?
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  • (ii) and (iii)
  • (i) and (iii)
  • (i), (ii) and (iii)
  • (i) and (ii)
Reaction between Ammonium chloride and Barium hydroxide is :
  • Exothermic reaction
  • Chemical change
  • Endothermic reaction
  • None of these
Physical changes are accompanied by:
  • Evolution of hydrogen gas
  • Change in state
  • Formation of a new yellow precipitate
  • Formation of a new compound.
In a reaction between zinc and hydrochloric acid, the changes accompanying a reaction are:
  • Evolution of gas and heat
  • Evolution of steam
  • Formation of precipitate
  • Formation of dazzling white light
If reaction between nitrogen and hydrogen to form ammonia is exothermic, then it will be accompanied by:
  • Change in state
  • Change in colour
  • Evolution of heat
  • Formation of precipitate
During an exothermic reaction:
  • Heat is absorbed.
  • There is no heat transfer.
  • Heat can either be absorbed or evolved.
  • Heat is evolved.
The reactions in which precipitate is formed are known as:
  • Exothermic reactions
  • Endothermic reactions
  • Precipitation reactions
  • Combustion reactions
As seen in the figure, two nails are carefully dipped in copper sulphate solution with the help of threads. What will happen when the nails are removed after half an hour?
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  • No change is observed
  • Nails turn blue in colour
  • Nails turn green in colour
  • Nails turn brown in colour
An example of a chemical reaction in which heat is evolved is:
  • Reaction between sodium and water
  • Reaction between lead nitrate and potassium iodide
  • Boiling of water
  • Ammonium chloride and Barium hydroxide
An example of reaction in which gas is evolved is:
  • Reaction between limestone and HCl
  • Burning of magnesium ribbon in air
  • Reaction between Calcium oxide and water
  • Reaction between lead nitrate and potassium iodide
Freezing of water is a:
  • Physical change
  • Chemical change
  • Both physical and chemical change
  • Exothermic reaction
An example of reaction in which precipitate is formed is:
  • Reaction between hydrogen and oxygen
  • Reaction between lead nitrate and potassium iodide
  • Reaction between hydrochloric acid and zinc.
  • Reaction between sodium and water
An example of a physical change is:
  • Burning of coal
  • Boiling of water
  • Reaction between lime and water
  • Burning of magnesium ribbon
The preparation of water from hydrogen and oxygen gas is accompanied by:
  • Evolution of coloured gas
  • Formation of precipitate
  • Formation of ashes
  • Change in state
Which of the following feature is common to both physical and chemical change?
  • Evolution of hydrogen gas
  • Formation of new precipitate
  • Evolution of carbon dioxide
  • Change in state and colour
A drop of colourless liquid is poured over blue litmus paper and it turns to red. The colourless liquid is:
  • sodium chloride solution
  • pure water
  • potassium hydroxide solution
  • dilute hydrochloric acid
What happens when dilute sulphuric acid is added to zinc granules? Select the correct option.
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  • Water and zinc sulphate is formed.
  • No reaction takes place.
  • Hydrogen and zinc sulphate is formed.
  • Hydrogen gas and zinc sulphide is formed.
Dissolving of quick lime in water is accompanied by:
  • Formation of precipitate
  • Evolution of heat
  • Change in colour
  • Change in state
Select the reaction which is not an exothermic reaction?
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  • A
  • B
  • C
  • D
Setting of cement is an example of:
  • Physical change
  • Precipitation reaction
  • Endothermic reaction
  • Exothermic reaction
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