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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] (f) Write the I.U.P.A.C. names of the following compounds: (i) (iii) (ii) [5] (iv) (v) (g)Identify P.Q.R.S.T in each case based on the information given below: [5] i) A deliquescent salt P, turns yellow on dissolving in water and give a reddish brown precipitate with sodium hydroxide solution ii) The white crystalline solid Q is soluble in water. It liberates a pungent smelling gas when heated with sodium hydroxide solution. iii) The reddish brown liquid R which turns colourless when ethylene gas is passed through it. iv) A white colour soluble salt S which give gelatinous white precipitate with sodium hydroxide solution v) An amphoteric oxide T, which is used for oxidation of ammonia. (h) Given below is representation of the Modern periodic table . Answer the questions based on the data given below [5] (i) Arrange the elements of the first group according to the increasing order of electron affinity (ii) Which element is the most metallic element? (iii) What is the similarity in electronic configuration of the halogens? (iv) Which is the most electronegative element from F and Cl (v) Which is the largest element of third period? SECTION-II(40 MARKS) (Attempt any four questions from this section) Question-02 (a) How will you prepare the following salts? (i)Sodium chloride salt by neutralization-titration (iii)Ferrous sulphate by simple displacement method. (v) Lead sulphate from lead nitrate. (b) Give the electron dot structure of the following: .(ii)Iron(III) chloride by direct combination. (iv) Barium sulphate by double decomposition reaction [5] (i) NH3 (ii) CH4 (iii) H3O+ (c) State the colour change on adding a few drops of H2SO4 to a very slightly alkaline solutions of the following indicators: [3] (i)Litmus solution (ii) Phenolphthalein (iii)Methyl orange [2] Question-03 (a) Give one test each to distinguish between the following pairs of chemicals: (i)Zinc nitrate solution and calcium nitrate solution. (ii)Sodium nitrate solutions and sodium chloride solutions. (iii)Iron(III) chloride solutions and copper chloride solutions [3] (b) (i) Draw a neat and well labelled diagram for the silver plating on an iron spoon. (ii) Copy and complete the following table related to electrolysis. [4] (c) Give balanced chemical equations for each of the following: (i)Lab preparation of ammonia using ammonium salts (ii)Reaction of ammonia with excess chlorine (iii) Reaction of ammonia with sulphuric acid [3] Question-04 (a)Draw a labeled diagram of electro purification of aluminium by Hoop s process and answer the following question with respect to it: (i)What is the material used as cathode and anode (ii) Write the electrolytic dissociation reaction taking place at cathode and anode when electricity is passed. [3] (b)Name the constituents of (i)Duralumin (ii) Solder (iii) Bronze [3] (c) Give balanced chemical equations for the action of sulphuric acid on each of the following: (i)Potassium hydrogen carbonate (ii) Sulphur [2] (d) In the contact process for the manufacture of sulphuric acid give the equations for the conversion of sulphur trioxide to sulphuric acid [2] Question-05 (a) A compound has the following percentage composition by mass: Carbon 54.55%, Hydrogen 9.09% and Oxygen 36.26%. Its vapour density is 44. Find the Empirical and Molecular formula of the compound. (H = 1; C = 12; O = 16) [3] (b) Draw different isomers having the following molecular formula: (i) C 5H12 (chain) (ii) C4H8 (position). [2] (iii) What is denatured alcohol? [1] (iv) Give two important uses of ethanol. [2] (v) Write equations for: (a) Preparation of ethanol by hydration of C 2H4. (b) Preparation of acetic acid from ethanol.[2] Question-06 (a) Give a chemical test to distinguish between : (i) Dilute Sulphuric acid and dilute hydrochloric acid ii) Dilute sulphuric acid and concentrated sulphuric acid [2] (b) Arrange the following as per the guidelines in the brackets : (i) K, Li, Na, (in increasing order of atomic size) (ii) Mg, Al, Na (in decreasing order of metallic nature) (iii) OH -1, SO4-2, Cl-1 (in increasing ease of discharge) [3] (c) The diagram given below shows the preparation of nitric acid in the laboratory. Observe the diagram and answer the questions given below: (i) Write a balanced reaction for the preparation of nitric acid. (ii) Why is concentrated sulphuric acid preferred over hydrochloric acid? (iii) How is nitric acid collected? (iv) What is the special feature of the apparatus? (v) What would happen if the temperature is increased above 200 0 C [5] Question-07 (a) Write the balanced chemical for each of the following : (i)Sodium thiosulphate is reacted with (dil).HCl. (iii) Lead Oxide is treated with conc. HCl (v)Manganese(IV) oxide and conc.HCl. (ii)Lead nitrate reacts with dil. HCl. (iv)Calcium bi carbonate reacts with dil.HCl. [5] (b) A sample of ammonium nitrate when heated yields 8.96 litres of steam. (measured at S.T.P) (i) What volume of dinitrogen oxide is produced at the same time as 8.96 litres of steam. [1] (ii) What mass of Ammonium nitrate should be heated to produce 8.96 litres of steam? (Given Atomic Weight of N =14, O =16, H =1) [2] (iii) Determine the percentage of Oxygen in Ammonium nitrate [2] ________________________________ END ____________________________________
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