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

approximate distance of 2m from the blackboard.
Draw ray diagrams to illustrate the formation of image of the blackboard writing by his
eye-lens when he is seated at the (i) last desk (ii) front desk.
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Name the type of lens that would help him to see clearly even when he is seated at the last
desk. Draw a ray diagram to illustrate how this lens helps him to see clearly.
12. State which of the subsequent chemical reactions will take place or not, giving suitable cause
for every.
Zn (s) + Cu SO4 (aq) ----> Zn SO4 (aq) + Cu (s)
Fe (s) + Zn SO4 (aq) ----> Fe SO4 (aq) + Zn (s)
Zn (s) + Fe SO4 (aq) ----> Zn SO4 (aq) + Fe (s)
13. (a) 2 lenses have power of (i) + 2D (ii) - 4D. What is the nature and focal length
of every lens.?
(b) An object is kept at a distance of 100cm from every of above lenses.
compute the (i) image distance (ii) magnification in every of the 2 cases.
14. The subsequent table indicates the position of 6 elements A, B, C, D, E and F in the periodic table.
Groups one two three to 12 13 14 15 16 17 18
Periods
2. A B C
3. D E F
Using the above table ans the subsequent ques. :
(a) Which element will form only covalent compunds?
(b) Which element is a metal with valency 2?
(c) Which element is a non-metal with valency of 3?
(d) Out of D and E, which 1 has a bigger atomic radius and why?
(e) Write a common name for the family of elements C and F.
15. An organic compound ‘A’ is widely used as a preservative in pickles and has a molecular
formula C2H2O2. This compound reacts with ethanol to form a sweet smelling
compound ‘B.
(i) Identify the compound ‘A’
(ii) Write the chemical formula for its reaction with ethanol to form compound ‘B’.
(iii) How can we get compound ‘A’ back from ‘B’?
(iv) Name the process and write corresponding chemical formula.
(v) Which gas is produced when compound ‘A’ reacts with washing soda?
write the chemical formula.
OR
(a) Why does carbon form largest number of compounds?
(b) Why are a few of these called saturated and other unsaturated compounds?
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(c) Which of these 2 is more reactive?

Earning:   Approval pending.