Page 83 - NCERT Science Class 10 English Medium

4. Explain the nature of the covalent bond using the bond formation in CH Cl.
3
5. Draw the electron dot structures for
(a) ethanoic acid.
(b) H S.
2
(c) propanone.
(d) F .
2
6. What is an homologous series? Explain with an example.
7. How can ethanol and ethanoic acid be differentiated on the basis of their physical
and chemical properties?
8. Why does micelle formation take place when soap is added to water? Will a micelle
be formed in other solvents such as ethanol also?
9. Why are carbon and its compounds used as fuels for most applications?
10. Explain the formation of scum when hard water is treated with soap.
11. What change will you observe if you test soap with litmus paper (red and blue)?
12. What is hydrogenation? What is its industrial application?
13. Which of the following hydrocarbons undergo addition reactions:
C H , C H , C H , C H and CH .
2 6 3 8 3 6 2 2 4
14. Give a test that can be used to differentiate between saturated and unsaturated
hydrocarbons.
15. Explain the mechanism of the cleaning action of soaps.

Group Activity

I Use molecular model kits to make models of the compounds you have learnt in
this Chapter.
II n Take about 20 mL of castor oil/cotton seed oil/linseed oil/soyabean oil in a
beaker. Add 30 mL of 20 % sodium hydroxide solution. Heat the mixture with
continuous stirring for a few minutes till the mixture thickens. Add 5-10 g of
common salt to this. Stir the mixture well and allow it to cool.
n You can cut out the soap in fancy shapes. You can also add perfume to the
soap before it sets.

78 Science

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