KARNATAKA SECONDARY EDUCATION EXAMINATION BOARD, MALLESWARAM, BANGALORE – 560 003
S. S. L. C. EXAMINATION, JUNE, 2017
Subject : SCIENCE ( / Chemistry )
1. According to Graham’s law of diffusion, at the given temperature and
pressure the rate of diffusion of a gas is
Ans. : (C) inversely proportional to the square root of its density.
4. ‘Norit’ is used in the manufacture of sugar because
Ans. : (C) sugar gets decolourised.
11. A few terms used in metallurgy are given in Column-A and their
meanings are given in Column-B. Match them and write the answers
along with its letter :
14. Define Charles law.
Ans. : At constant pressure, the volume of a fixed mass of a gas is directly
proportional to its absolute temperature.
18. The electrochemical equivalent of copper and gold are 0·0003 gm/coulomb and 0·000681 gm/coulomb respectively. If the equal amount of current is passed for the equal time interval in copper and gold voltameters, then in which voltameter the deposition of the metal at the cathode is more ? Why ?
Ans. : Gold Because, the mass of the substance deposited is directly proportional to its chemical equivalence.
21. Explain the method of manufacturing 95% pure ethyl alcohol from
molasses.
Ans. : Molasses is diluted with water and acidified by adding dilute sulphuric acid.
Yeast is added and the temperature is maintained at 308 K. Fermented matter is called Wort.
Wart is fractionally distilled to get 95% pure alcohol.
22. Draw the diagram of the apparatus used in electroplating.
Ans. :
29. Draw the diagram of the apparatus used in the electrolytic refining of copper.
Ans. :
32. Name the type of glass used in the following situations :
(a) Manufacture of laboratory equipments
(b) Manufacture of lens
(c) Manufacture of window glass
(d) Used as wind shield in aeroplane industries.
OR
Name the type of paper used in the following situations :
(a) To wipe the face
(b) Manufacture of post card
(c) To separate fine solids from liquids
(d) To wrap the cookies.
Ans. : (a) Borosilicate glass
(b) Lead glass
(c) Soda glass
(d) Safety glass
OR
(a) Tissue paper
b) Card board paper
(c) Filter paper
(d) Wax paper.
33. Explain the method of extraction of crystalline silicon with chemical
equation.
Ans. : Crystalline silicon is obtained when excess of silica is heated with coke in
the electric furnace in the absence of air.
34. In a specific group of unsaturated hydrocarbons, though the ratio of carbon and hydrogen atoms is
1 : 2, CH 2 is not the first member of
those hydrocarbons. What is the reason for this ? Write the structural
formula of the first member of that hydrocarbon group.
Ans. : The tetravalent property of carbon is not satisfied. OR carbon cannot
form double bond with hydrogen atom.
39. The electronic configuration of four elements is given in the following
table :
(a) Which element has greatest atomic size in these elements ? Why ?
(b) Among these elements, the element having least atomic size,
belongs to which period ? Why ?
Ans. : a) 'C' element has greater atomic size. Because, it has more number (4) of shells.
b) It belongs to 2nd period. ( The element 'B' has least atomic radius as the number of shells is less )
Because, the electronic configuration of the element 'B' is ended in
2nd shell.
(a) What are functional groups ? Write the structural formula of the
compound obtained when one atom of hydrogen in ‘Ethane’ is
replaced by — CHO group.
(b) Write the balanced chemical equations for the four chemical
reactions occurring when the mixture of methane and chlorine is
exposed to ultraviolet light, till the production of
tetrachloromethane.
OR
(a) Explain the preparation of methane with chemical equation. Name
the products formed when methane completely burns in oxygen.
(b) Oils have very little shelf life. What is the reason ?
Ans. : (a) The specific groups of atoms or bonds within molecules that are
responsible for the characteristic chemical reactions of those
molecules.
OR
(a) When a mixture of sodium acetate and sodalime is heated in a hard
glass test tube, methane gas is formed.
(b) Unsaturated, chemically reactive,
They oxidis in air. ( any two )
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