MAHESH TUTORIALS I.C.S.E. GRADE - X (2017-2018) Exam No. : MT/ICSE/SEMI PRELIM - I-SET -A 008 Sulphuric acid, Ammonia, Analytical Chemistry, Organic Chemistry HCl, Nitric acid, Metallurgy Chemistry SCIENCE PAPER - 3 (2 hours) Answers to this Paper must be written on the paper provided separately. You will not be allowed to write during the first l5 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. Attempt all questions from Section I and 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 answer from the choices A, B, C & D in each case : [5] (i) The organic compound, which gives a white precipitate with ammoniacal silver nitrate and undergoes an addition reaction. (A) Ethane (B) Methane (ii) Ethyne (D) Ethanol Hydrogen chloride gas being highly soluble in the water is dried by. (A) (B) (D) Anhydrous calcium chloride Phosphorous pentoxide Quick lime conc.sulphuric acid < 200ºC (iii) In the given equation: KNO 3 + H 2 SO 4 KHSO 4 + HNO 3 (conc) Identify the role played by conc.h 2 SO 4. (A) Non-volatile acid (B) Oxidising agent Dehydrating agent (D) None of the above Copyright reserved. This Paper consists of 6 printed pages.
... 2... (iv) Ammonia can be obtained by adding water to : (A) Ammonium chloride (B) Ammonium nitrite Calcium nitride (D) Calcium nitrite (v) The functional group present in ethanol is : (A) C O (B) OH C HO (D) COOH (B) Match the following ions in column A with their correct precipitate formed when sodium hydroxide solution is added to the solutions in column B. [5] Column A Column B 1. Pb 2+ a) Reddish brown 2. Fe 2+ b) Pale blue 3. Zn 2+ c) Dirty green 4. Fe 3+ d) Chalky white soluble in excess 5. Cu 2+ e) Gelatinous white soluble in excess. Give reasons for the following : [5] 1. In the contact process, sulphur trioxide is not converted to sulphuric acid by reacting it with water. 2. Liquid ammonia is used as a refrigerant in ice plants. 3. Sulphuric acid is not used to dry hydrogen sulphide gas. 4. Ethyne is more reactive than ethane. 5. Concentrated sulphuric acid may be added during, esterification of acetic acid. (D) Answer the following questions with respect to industrial preparation of nitric acid. [5] 1. Give the equations of reactions for the preparation. 2. How is the temperature maintained in Ostwald s process? 3. Why is higher ratio of the reactant air required in the manufacture of nitric acid? (E) State the observation for each of the following : [5] 1. Neutral litmus solution is added to an alkaline solution. 2. Ammonia gas is burnt in an atmosphere of excess oxygen. 3. Sugar crystals are added to conc. sulphuric acid. 4. Bromine vapours are passed into a solution of ethyne in carbon tetrachloride. 5. Acetic acid is added to neutral FeCl 3 Solution.
... 3... (F) In the laboratory preparation of hydrochloric acid, hydrogen chloride gas is dissolved in water. [5] 1. Draw a diagram to show the arrangement used for the absorption of HCl gas in water and name it. 2. State why such an arrangement is necessary. Give two reasons for the same. 3. Write balanced chemical equations for the preparation of HCl gas when the reactants are above 200ºC. (G) Give balanced equations for the following reactions : [5] 1. Sodium hydrogen carbonate reacts with dilute sulphuric acid. 2. Action of concentrated sulphuric acid on carbon. 3. Reaction of ammonia with excess chlorine. 4. Acetic acid reacts with sodium at room temperature. 5. Water is added to calcium carbide. (H) Write the equations for the following reactions : [5] 1. Bromoethane on boiling with alcoholic KOH. 2. Sodium priopionoate and soda lime. 3. Ethanol vapours and alumina [Al 2 O 3 ] at 350 o C. 4. Chlorination of ethyne in presence of CCl 4 solvent. 5. Ethanol with ethanoic acid in presence of conc. H 2 SO 4. Question 2 SECTION II (40 Marks) Attempt any four questions from this section. (A) Give balanced equations for the following conversions A, B, C & D [4] A 1. NH OH NH SO NH B 4 4 2 4 3 2. NH Cl NH N C D 4 3 2 (B) State your observations when dilute hydrochloric acid is added to: [3] 1. Lead nitrate soln. & the mixture is heated. 2. Copper carbonate 3. Sodium thiosulphate. Aluminium is used in thermite welding : [3] 1. What is thermit? 2. What is ignition mixture? 3. Write reaction for process.
... 4... Question 3 (A) Match the properties and uses of metals or alloys in List 1 with the correct answer from List 2. [5] List 1 List 2 1. Easily cast, expands on solidification and used in A. Lead metal making pipes 2. Is light and used in radiation shields and making B. Brass bullets 3. Contains Cu and Zn, is hard and silvery and is C. Pig iron used in decorative articles 4. Is stronger than Al, light and used in making light D. Stainless tools steel 5. Is lustrous, corrosion resistant and used in surgical E. Duralumin instruments (B) Define the term catenation. [1] Compound X is bubbled through bromine dissolved in CCl 4 and the product formed is CH 2 Br CH 2 Br. [4] 1. Draw the structural formula of X. 2. What type of reaction X has undergone? 3. Name the compound formed when steam reacts with X in the presence of an acid, eg. phosphoric acid. 4. What is the procedure for converting the product formed in 3) above, back to X. Question 4 (A) Explain the following : [4] 1. Dil. HNO 3 is generally considered a typical acid but not so in its reaction with metals. 2. When it is left standing in a glass bottle, concentrated nitric acid appears yellow. 3. In the laboratory preparation of nitric acid, an all glass apparatus is used. 4. NO 2 is called a mixed acid anhydride. (B) Give reasons why sulphuric acid [2] 1. behaves as an acid when dilute. 2. is dibasic in nature.
... 5... Give balanced equations with conditions, if any, for the following conversions 1 to 4. [4] 1. Sodium Chloride Hydrogen Chloride 2. Hydrogen Chloride Iron (II) chloride 3. Hydrogen Chloride Ammonium chloride 4. Hydrogen Chloride Lead chloride Question 5 (A) Using their structural formulae identify the functional group by circling them. [3] 1. Dimethyl ether 2. 2 - Pentanone 3. Propanoic acid (B) Answer the following questions with respect to manufacture of ammonia by Haber s process. [3] 1. Name the reactants used. 2. How are the above reactants obtained in pure state? 3. Give the balanced chemical equation for the reaction. Al is extracted from its ore, Bauxite. The ore is first purified. [4] 1. Write 3 balanced equations for the purification of bauxite by Hall s process. 2. Name a chemical used for dissolving aluminium oxide. Question 6 (A) The molecules of alkene family are represented by C n H 2n answer the following : [4] 1. What is the name of the alkene when n = 4? 2. What is the molecular formula of the alkene when n = 4? 3. What is the molecular formula of alkene when there are 10 H atoms in it? 4. Give the structural formula of the third member of the alkene family. (B) Study the figure given along side and answer questions that follow : [3] 1. Give a balanced equation for the reaction represented. 2. State the change in colour if the product X formed is reacted with anhydrous copper sulphate. 3. Is the final product formed in flask A a neutral or an acidic oxide.
... 6... Define [3] (i) Flux (ii) Ore (iii) Smelting Question 7 (A) Select the letters A, B, C, D or E, which form the gaseous products of the reactions from 1 to 4. [4] A: Nitrogen dioxide only B: Nitric oxide only C: Hydrogen D: Nitrogen dioxide and Oxygen. E: Nitrogen dioxide with Carbon dioxide 1. Reaction of manganese with cold very dil. nitric acid. 2. Reaction of sulphur with conc. nitric acid. 3. Reaction of zinc with dil. nitric acid. 4. Reaction of carbon with hot conc. nitric acid. (B) Find odd man out in each case and explain your choice. [2] 1. C 2 H 2, C 5 H 10, C 6 H 12, C 4 H 8 2. Nitric acid, Sulphuric acid, Carbonic acid, Hydrochloric acid. From ethyne, ethanol, acetic acid, ethene, methane. Choose the one which relates to 1 to 4. [4] 1. An unsaturated hydrocarbon used for welding purpose. 2. An organic compound whose functional group is carboxyl. 3. A hydrocarbon which on catalytic hydrogenation gives a saturated hydrocarbon. 4. An Organic compound used as a thermometric liquid. All the Best