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ICSE Chemistry: Model Paper 2 Answers to this Paper must be written on the paper provided separately. You will not be allowed to write during the first 15 minutes. This time is to be spent in reading the Question Paper. The time given at the head of this paper is the time allowed for writing the answers. Section I is compulsory. Attempt any four questions from Section II. The intended marks for questions or parts of questions are given in brackets []. SECTION I (40 Marks) Attempt all questions from this Section Question 1: (a) Select the correct alternative from the given bracket to make the statement true: (i) A solution which on heating with CaCO3, we get the CO2 gas is _________ [conc. H2SO4 / dil. HCl / dil. H2SO4]. (ii) A solution which is used to distinguish an ammonium salt from a sodium salt is ______ [CuCl2 soln / NH4OH / dil. H2SO4 / AgNO3 soln.] (iii) The pH of blood is 7.4, of saliva is 6.5 and a dil. acid 4.5. A solution that is alkaline is ____________ [dil. acid / saliva / blood]. (iv) Decomposition of ________ [NaCl / NaHCO3 / NaNO3] by dil. H2SO4 an unstable acid is formed. (v) A metal which reacts with an alkali to liberate hydrogen is _______ [iron / copper / aluminium]. (b) Give balanced equations for the conversion of the following: (i) An alkane to an alcohol (ii) An alkene to an alkane (iii) An alkyne to an alkene (iv) An alcohol to an alkene (v) An aldehyde to an acid. (c) Give reasons for the following: (i) Hydrogen sulphide is used as an analytical reagent in the laboratory. (ii) Conc. sulphuric acid is used in the laboratory preparation of iodine from hydrogen iodide. (iii) To distinguish between dil. H2SO4 and dil. HNO3, barium chloride can be used. (iv) The gas obtained when zinc reacts with dil. H2SO4 or conc. H2SO4 are different. (v) H2S and SO2 decolourises acidified KMnO4 solution, even then the two gases can be distinguished with the same. (d) Fill in the blanks from the given alternatives in the brackets: (i) Lead nitrate is a / an ___________ [acid / normal] salt of nitric acid. (ii) When H2S reacts with Dil. HNO3, the oxidized product obtained is ________ [Sulphur / Sulphur dioxide / sulphuric acid] (iii) A nitrate on heating melts and liberates only one neutral gas is ________ [lead nitrate / sodium nitrate / silver nitrate / calcium nitrate]. (iv) A mineral acid obtained from conc. nitric acid on reaction with a non-metal is ________ [carbonic acid / sulphuric acid / hydrochloric acid]. (v) The reaction of __________ [calcium oxide / calcium carbonate / calcium sulphate] with dilute nitric acid is an example of neutralization reaction. Jaydip.Chaudhuri 1
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