Except for the following questions, all the remaining questions have been asked in Set I.
SECTION A
Q. 4. Write the formulation for the functional groups of alcohols and carboxylic acids. 1
Q. 10. State the chemical property in each case on which the following uses of baking soda are based:
(a) as an antacid
(b) as a constituent of baking powder 2
Q. 12. A convex lens has focal length of 20 cm. Calculate at what distance from the lens should the object be placed so that it forms an image at 40 cm on the other side of the lens?
State the nature of the image formed. 3
Q. 13. (i) State the formula showing how the current I in a conductor varies when the potential difference V applied across it is increased stepwise.
(ii) Show this relationship also On a schematic graph.
(iii) Calculate the resistance of a conductor if the current flowing through it is 0.2 ampere when the applied potential difference is 0.8 volt. 3
Q. 14. Write chemical equations for the reactions taking place when: 3
(i) steam is passed over red hot iron.
(ii) sulphur dioxide gas is dissolved in water.
(iii) a solution of ammonia is mixed with a solution of aluminium chloride.
Q. 15. Give reasons for the following:
(i) Metals conduct electricity.
(ii) Reaction of nitric acid with metals generally does not evolve hydrogen gas.
(iii) For making gold ornaments, 22-carat gold is preferred to 24-carat gold. 3
SECTION B
Q. 21. Which hormone helps in lowering the level of blood glucose in human beings? 1
Q. 22. We suddenly withdraw our hand when a pin pricks. Name the type of response involved in this action. 1
Q. 23. Who proposed the theory of natural selection? Why was this theory criticized? 1
Q. 24. Give one example each of a natural and a man-made source of air pollution. 2
Or
Suggest two practices that can help in controlling air pollution. 2
Q. 27. (i) Who isolated DNA for the first time from pus cells?
(ii) Why is DNA called a polynucleotide?
(iii) Name two purine nitrogenous bases found in a DNA molecule. 3
Q. 29. (i) What is menopause?
(ii) Draw a labelled diagram to show the reproductive system in women. 3
