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GOLDCREST HIGH-LATUR ON THE WINGS OF EXCELLENCE PRELIM-01 SUBJECT:-CHEMISTRY TIME: 2 HOURS DATE:-09/01/2017 GRADE-10 MARKS:80 General Instructions 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 the paper is the time allotted for writing the answers. Attempt all questions from Section I and any four questions from Section II. The intended marks of questions or parts of questions are given in brackets [ ]. SECTION-I(40 Marks) Question-01 (a) Choose the most appropriate answer. [5] (i) Which of the following is a common characteristic of a covalent compound? A .High melting point. B. Conducts electricity when it is in the molten state. C. Consists of molecules. D. Always soluble in water. (ii) Ammonium hydroxide will produce a reddish brown precipitate when added to a solution of : A. CuSO4 B. Zn(NO3)2 C. FeSO4 D. FeCl3 (iii) A salt which in solution gives a bluish white precipitate with NaOH solution and a white precipitate with BaCl 2 solution is: A CuSO4 B. FeSO4 C. Fe2 (SO4 )3 D. Cu Cl2 (iv)Which of the following would weigh the least? A. 2gram of Nitrogen B. 1 mole of silver C. 22.4 litres of oxygen gas at 1 atmospheric pressure and 273K D.6 .02 x 10 23 atoms of carbon (v)Bonding in this molecule can be understood to involve coordinate bonding: A.Carbon tetrachloride B.Hydrogen C.Hydrogen chloride D.Ammonium Chloride (b)Identify the gas evolved in the following reaction when: (i)Potassium Permanganate is treated with conc. Hydrochloric acid (ii)Calcium bicarbonate treated with conc. Hydrochloric acid. (iii)Action of warm water on magnesium nitride (iv)Action of dilute Nitric acid on Copper sulphate (v)Action of conc. Sulphuric acid on Ethanol [5] (c) Name the organic compound prepared by each of the following reactions: (i) CH3 COONa + NaOH (ii) CaC2 + H2O (iv) C2H5Br + KOH (aq) (v) C2H5OH + CH3COOH (iii) C2H5Br + KOH (alc) (d) The equation for the action of heat on calcium nitrate is: 2Ca(NO3)2 2CaO + 4 NO2 + O2 (i) How many moles of NO2 are produced when 1 mole of Ca (NO3)2 decomposes? (ii) What volume of O2 at S.T.P. will be produced on heating 65.6 g of Ca (NO3)2 ? (iii) Find out the mass of CaO formed when 65.6 g of Ca(NO3)2 is heated. (iv) Find out the mass of Ca(NO3)2, required to produce 5 moles of gaseous products. (v) Find out the mass of Ca(NO3)2 required to produce 44. 8 L of NO2 at S.T.P. (Relative molecular mass of Ca(NO 3)2 = 164 and of CaO = 56) [5] [5] (e) Give reason for the following: (i)Magnesium is placed above than aluminium in the activity series. (ii)Alkali metals are strong reducing agents. (iii) Oxides of highly active metals can not be reduced by C or CO or H 2 (iv)Anode electrode has got to be replaced From time to time in electrolyte reduction of fused alumina in Hall-Heroult s process. (v) Use of cryolite and Fluorspar in the electrolyte reduction of alumina in Hall s process [5]
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