Combination Reaction

Materials required:

Procedure:

As performed in a real lab:

  • Take a small quantity of calcium oxide (quick lime) in a beaker.
  • Slowly add water to the quick lime taken in the beaker. Pour enough water so that the quick lime remains submerged in the water.
  • Touch the beaker with fingers to note the temperature.
  • Leave the beaker undisturbed for some time.
  • Take a small quantity of clear solution from the beaker in a test tube and blow exhaled air into the lime water.

Simulator Procedure (as performed through the Online Labs)

  • Drag the spatula containing quicklime over to the empty beaker to transfer the contents into it.
  • Drag the beaker containing distilled water to pour it into the beaker containing quick lime.
  • Wait for some time till the quick lime reacts with water to form a suspension of slaked lime.
  • You can see that the thermometer shows an increase in temperature.
  • View the inference by clicking on the inference icon.
  • Click on the ‘Next’ button to go to the next process.
  • You will get a clear solution of lime water as the suspension of slaked lime settles down at the bottom of the beaker.
  • Now, drag the dropper and dip it in the beaker to suck lime water in it and then drag it towards the test tube to pour the lime water into it.
  • Drag the cork with the bent tube towards the test tube to close it.
  • Click on the ‘Next’ button to go to the next process.
  • Click on the blow button to blow in exhaled air into the test tube containing lime water.
  • The lime turns milky.
  • View the inference by clicking on the inference icon.
  • You can click on the ‘Reset’ button to redo the experiment.

Note: Click on the ‘HELP’ button to see the instructions

Observations:

  • When water is added to quick lime, a suspension of slaked lime is formed.
  • On touching the beaker we feel it is hot.
  • A clear solution appears as the suspension of slaked lime settles down to the bottom of the beaker.
  • On blowing exhaled air that contains sufficient carbon dioxide, lime water turns milky.

Inferences:

  • Quick lime reacts vigorously with water to produce slaked lime releasing a large amount of heat. So the reaction is highly exothermic.


                                                                                                                                                     

  • Slaked lime is only slightly soluble in water, so it forms a suspension of slaked lime in water.
  • The clear solution obtained after the suspension settles is called lime water.
  • Exhaled air contains CO2 which turns lime water milky.
  • Calcium oxide and water react to form only a single product, calcium hydroxide. So the reaction is a combination reaction.

Precautions:

 

Enjoy your experiment!!

 

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