Central Institute of Higher Tibetan Studies 2009 CBSE CLASS X - Question Paper

8. A learner performs an experiment to study the magnetic effect of current around a current
carrying straight conductor. He reports that
(i) the direction of deflection of the north pole of a compass needle kept at a provided point
near the conductor remains unaffected even when the terminals of the battery sending
current in the wire are inter changed.
(ii) for a provided battery, the degree of deflection of a N-pole reduces when the compass
is kept at a point farther away from the conductor.
Which of the above observations of the learner is incorrect and why?
9. A housewife wanted her house to be whitewashed. She bought 10kg of quick lime from
the market and dissolved it in 30 litres of water. On adding lime to water she noticed that
the water started boiling even when it was not being heated. provide cause for her
observation. Write the corresponding chemical formula and name the product formed.
10. Write the electron - dot structure for sodium and chlorine atoms. How do these form a
chemical bond? Name the kind of bond so formed. Why does a compond so formed have
high melting point?
11. 2 carbon compounds A and B have the molecular formula C3 H8 and C3 H6 respectively.
Which 1 of the 2 is most likely to show addition reaction? Justify your ans. discuss
with the help of a chemical equation, how an addition reaction is useful in vegetable ghee
industry.
12. A beam of white light falling on a glass prism gets split up into 7 colours marked one to
7 as shown in the diagram.
A learner makes the subsequent statements about the spectrum observed
on the screen.
a) The colours at positions marked three and five are similar
to the colour of the sky and the core of a hard boiled
egg respectively.
Is the above statement made by the learner accurate
or incorrect? Justify.
b) Which 2 positions correspond closely to the
colour of
319
(i) a solution of potassium permanganate?
(ii) ‘danger’ or stop signal lights?
13. Baking soda is used in small amount in making bread and cake. It helps to make these
soft and spongy. An aqueous solution of baking soda turns red litmus blue. It is also used
in soda acid fire extinguisher.
Use this info to ans the subsequent questions:
(i) How does Baking Soda help to make cakes and bread soft and spongy?
(ii) How does it help in extinguishing fire?

Earning:   Approval pending.