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GOLDCREST HIGH, LATUR TRIAL EXAMINATION (2018-19) GRADE: 10 SUBJECT: SCIENCE PAPER-2 (CHEMISTRY) Time: 2 Hours Max. Marks: 80 Answer to this question must be written on the paper provided separately. You will not be allowed to write answers for the first 15 minutes. This time is to be spent on reading the question paper. The time given at the head of this paper is the time allotted for the writing the answer. The paper is divided into two sections. Attempt all questions from Section A and any four questions from Section B. 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) Choose the most appropriate answer. (i) The element with the highest ionization potential in the periodic table is: A. He B. Ne C. Ar [5] D. Xe (ii) The ratio between the number of molecules in 2g of hydrogen and 32g of oxygen is (H-1,O-16): A. 1:2 B. 1:0.01 C.1:1 D. 0.01:1 (iii) A salt which in solution gives a bluish white precipitate with NaOH solution and a white precipitate with BaCl2 solution is: A CuSO4 B. FeSO4 C. Fe2 (SO4 )3 D. Cu Cl2 (iv) A strong electrolyte from the following is: A. Acetic acid B. Oxalic acid C. Ammonium hydroxide D. Sodium hydroxide (v) Which of the following reactions gives copper as a product: A. Passing dry ammonia over heated copper oxide B. Adding dil, HCl to Copper Oxide C. Heating Copper oxide D. Passing oxygen over heated copper oxide (b) State one relevant observation for each of the following: (i) Dilute Hydrochloric acid is added to Silver Nitrate solution. (ii) Concentrated Nitric acid is added to Copper turnings. (iii) Mixture of Ammonium Chloride and Sodium Hydroxide is heated. (iv) Ammonium hydroxide solution is added in excess to copper sulphate solution. (v) NaOH solution is added to calcium nitrate solution [5] (c) Write balanced chemical equations for each of the following: (i) Catalytic oxidation of ammonia. (ii) Action of concentrated nitric acid on Sulphur. (iii) Action of dilute hydrochloric acid on iron. (iv) Action of concentrated sodium hydroxide on Zinc oxide. (v) Reaction between acetic acid with ethanol in the presence of concentrated sulphuric acid. [5] TRIAL EX -1/CHE/2018-19/KSH This question paper consists of 6 printed pages Page 1 (d) Complete the following calculations. Show working for complete credit. (i) What is the mass of nitrogen in 1000 kg urea, CO(NH2)2 ? Answer correct to nearest kg. [5] (ii) Calculate the number of moles and the number of molecules present in 1.4 g of ethylene gas. What is the volume occupied by the same amount of ethylene? What is the vapour density of ethylene? (C-12,H-1). (iii) 88g of a compound of carbon and oxygen only, contains 64g of oxygen. Determine its empirical formula. (C-12,O-16) (e) The following statements are correct only under certain conditions. Rewrite each statement including appropriate conditions underlined in your answers: (i) Hydrogen chloride gas is a covalent compound. (ii) Ammonia turns red litmus blue. (iii) Sulphuric acid is least volatile acid. (iv) Magnesium reacts with Nitrogen to form Magnesium nitride. (v) Hydrogen chloride is soluble in water. [5] (f) (i)Draw the structural formula for each of the following: [2] (a) The third member of carboxylic acid C4H10 which has a branched chain (b) Formaldehyde (c) Formic acid (d) An isomer of (ii) Write balanced chemical equation for the preparation of each of the following salts: (a) Ammonium Sulphate crystals (b) Lead carbonate Lead nitrate Lead Sulphate (c) Sodium Sulphate from sodium carbonate [3] (g) Arrange the following as per the instruction given in the brackets. [5] (i) Li, F, N (ii) Na, Al , Cl (iii) O2, N2, Cl2 (iv) Zn2+, Na+, Cu+2 (v) Br , F , Cl [increasing order of electronegativity] [increasing order of Ionization potential ] [increasing order of number of covalent bonds] [order of preference of discharge at the cathode] [Decreasing order of atomic radius] (h) Elements A,B,C,D,E and F have the following atomic numbers: A-12. B-17, C-18, D-7, E-9, F-11. Answer the following with respect to the information provided above. [5] (i) Which one of them has the lowest electron affinity? (ii) Which one of them has the highest electron affinity? (iii) Which one of them has the largest atomic size.? (iv) Which one of them belongs to third period and has the highest ionisation potential.? (v) Draw an electron dot diagram to show the compound between A and B. TRIAL EX -1/CHE/2018-19/KSH This question paper consists of 6 printed pages Page 2 SECTION-II (40 MARKS) (Attempt any four questions from this section) Question-2 (a) Give a chemical test to distinguish between the following pairs of chemicals: (i) Calcium nitrate and potassium nitrate (using a flame test) (iii) Calcium nitrate and zinc nitrate [3] (ii) Sodium chloride and sodium sulphide (b) Ammonia dissolves in water to produce neutral positively charged ions. Draw the structure of this positive ions (c) Give balanced chemical equations for the preparation of the following: (i) Chloroform from methane (ii) Ethyl acetate from ethanol (iii) Ethanol from ethene (iv)Ethyne from ethylene dibromide [1] [4] (d) Name the most common ore of Aluminium, Zinc and Iron. Name the processes by which the named ores are concentrated. [2] Question-3 (a) Give balanced chemical equations for the conversions A to K [4] (b) State the property of alloys given below which make it useful for the particular application [2] (i) Solder in electric fuse (ii) Duralumin in air crafts (iii) Stainless steel in cutlery (iv) Bronze in statues (c) Write one point difference between Electron affinity and Electronegativity (d) What is Levigation and Pulverisation ? [1] [1] (e) Give the balanced equations for the following conversions: [2] TRIAL EX -1/CHE/2018-19/KSH This question paper consists of 6 printed pages Page 3 Question-4 (a) Give balanced chemical equations for the action of nitric acid on each of the following: (i) Copper turnings [2] (ii) Phosphorus (b) Complete the table:NAME OF THE PROCESS OSTWALD S PROCESS HABER S PROCESS INPUT S [2] CATALYST TEMPERATURE PRESSUR E OUTPU T PROMOTER(IF ) CHEMICA L EQUATION (c) Draw different isomers having the following molecular formula: (i) C5H12 (chain) (ii) C4H8 (position and chain). [2] (d) A gaseous compound of nitrogen and hydrogen contains 12.5 % hydrogen by mass. Find the molecular formula of the compound if its relative molecular mass is 37. (N-14, H-1). [2] (e) Name the organic compound prepared by each of the following reactions: (i) C2H5Br + KOH (alc) [2] (ii) C2H5Br + KOH (aq) Question-5 (a) Calcium carbide was added to a conical flask and was treated with water. A gas (G) evolved out. (i) Name the gas (G) (ii) Draw its graphic structure (iii) Write balanced chemical equation for its complete combustion in oxygen. (iv) Mention one economic importance of gas (G). [2] (b) State the inference drawn from the following observations: [5] .(i) A piece of iron is added to copper [II] sulphate solution. (ii) A paper dipped in potassium permanganate solution is put on the mouth of a test tube containing Sulphur dioxide gas. (iii) On mixing a solution of calcium chloride with a solution of sodium carbonate. (iv). Excess of ammonium hydroxide is added to a substance obtained by adding hydrochloric acid in silver nitrate solution (v) Concentrated hydrochloric acid is added to lead (IV) oxide with warming (c) (i)Calculate the percentage of sodium in sodium aluminium fluoride (Na3 AlF6) correct to the nearest whole number. (F -19, Na - 23, Al - 27) [1] (ii) LPG stands for liquefied petroleum gas .Varieties of LPG are marketed including a mixture of propane (60%) and butane (40%).If 10 litres of this mixture is burnt, find the total volume of carbon dioxide added to the atmosphere. Combustion reaction can be represented as: C3H8 + 5O2 3CO2 + 4 H2O 2 C4H10 +13 O2 8CO2 + 10 H2O [2] TRIAL EX -1/CHE/2018-19/KSH This question paper consists of 6 printed pages Page 4 Question-6 (a) The equation for the action of heat on calcium nitrate is: 2 Ca(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(NO3)2 = 164 and of CaO = 56) [5] (b) Copy and complete the following table related to electrolysis. [3] S.N O NAME OF THE ELECTROLYTE NAME OF CATHODE NAME OF ANODE 1 H2O (acidified) Platinum foil Platinum foil 2 CuSO4 (aq) Copper Carbon 3. Sodium silver cyanide (aq) Spoon Silver block REACTION AT CATHODE REACTION AT ANODE (c) (i) On warm weather, concentrated nitric acid turns yellow. Why is it so? How can you render this acid colourless? (ii) Dark rings are formed on wooden shelves where bottles of conc. sulphuric acid are kept [2] Question-7 (a) The diagram gives the arrangement of the apparatus used for the preparation alkaline gas. [4] (i) Identify X and Y. Explain why ammonium nitrate is not used in the preparation of ammonia. (ii) Name the compound normally used as a drying agent during the process . (iii) How the gas is collected? (iv)Explain why it is not collected over water (v)In the laboratory preparation of ammonia from ammonium chloride, the mouth of the flask in which the reaction is carried is kept slanting downwards. Why. (vi)The apparatus used for lab.preparation of ammonia gas should be dry. Why? (vii)Ammonia gas is not dried using drying agents like conc.H2SO4,P2O5,and fused calcium chloride.Why TRIAL EX -1/CHE/2018-19/KSH This question paper consists of 6 printed pages Page 5 (b) The reaction between calcium carbonate and hydrochloric acid is as follows: [2] CaCO3 + 2HCl CaCl2 + H2O + CO2 (i) Calculate the number of moles of hydrochloric acid that reacts with 10g of calcium carbonate (ii) If the calcium carbonate used had 20% of calcium chloride as impurity, what would be the volume of carbon dioxide liberated? (iii) How many molecules of water are formed? [Avogadro s No = 6 x 1023 At wt. Ca = 40 C = 12, H =1 Cl = 35.5 O =16] (c) Write the IUPAC name of the following: (i) [2] (ii) (d) X is a reddish brown element. When heated with dilute nitric acid, it gives out a colourless gas Y which turns into a reddish-brown gas on coming contact with air. A blue solution of a substance Z is also formed. The crystals of substance Z when heated give out the reddish brown gas along with another gas. A black residue M is left behind. (i) Name the substance X (ii) Write an equation for the reaction of substance X with dilute nitric acid and name the gas Y. (iii) Name the substance Z and M. Write an equation for the action of heat on substance Z TRIAL EX -1/CHE/2018-19/KSH This question paper consists of 6 printed pages [2] Page 6
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