chapter 4 carbon and its compound dec 2015 | Page 11

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An emulsion is thus formed by soap molecule. The cloth needs to be
mechanically agitated to remove the dirt particles from the cloth.

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Scum : The magnesium and calcium salts present in hard water reacts with
soap molecule to form insoluble products called scum, thus obstructing the
cleansing action. Use of detergents overcome this problem as the detergent
molecule prevents the formation of insoluble product and thus clothes get
cleaned.

EXERCISE
(Question Bank)
1MARK
1.

How an atom of carbon attain noble gas configuration?

2.

Draw the electron dot structure of a molecule of water.

3.

Define catenation.

4.

The kerosene/gas stove used at home has inlets for air. Give reason.

5.

Write only the chemical equation for dehydration of ethanol by hot conc.
Sulphuric acid.

6.

Write the number of covalent bonds present in propane.

7.

Define the term: oxidising agent.

8.

Write the formula for first member of ketone.

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