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CHEMISTRY SCIENCE Paper -2 (Two Hours) Answer 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 answer. 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) Fill in the blank: [5] (i) The basicity of acetic acid is (ii) The compound formed when ethanol reacts with sodium is . (iii) Quicklime is not used to dry HCl gas because ... (iv) Ammonia gas is collected by . (v) Cold, dilute nitric acid reacts with copper to form ... (b) Choose the correct answer from the options given below. (i) (ii) How many number of atoms present in 1.6 g of methane? (I) 6.02 x 1022 (II) 3.01 x 1024 (III) 6.02 x 1024 (IV) 3.01 x 1023 Which of the following have more weight at STP? (I) One litre of chlorine (II) one litre of hydrogen (III) One litre of nitrogen (IV) One litre of oxygen 1 ICSE (Grade : X) | CHEMISTRY (SCIENCE Paper-II) | Pre Board Exam-II [5] (iii) (iv) (v) (c) Number of moles of CaCO3 which contains 1.5 moles of oxygen atom, is (I) 0.5 (II) 2.0 (III) 1.0 (IV) 1.5 If you need 3.011x1023 atoms of Na for a chemical reaction, what is the mass of the metal required (relative atomic mass of Na= 23) ? (I) 12.5 g (II) 10.5 g (III) 11.5 g (IV) 11.2 g How many atoms of Na are present in 46 g of the metal (atomic mass of Na = 23)? (I) 1.2044 x 1024 (II) 1.1044 x 1024 (III) 1.3044 x 1024 (IV) 1.2244 x 1024 Name the following: [5] (i) A salt on heating with concentrated sulphuric acid changes from blue to white. (ii) The oxide of sulphur which causes acid rain. (iii) A catalyst used in Ostwald s process. (iv) An alkaline gas which gives dense white fumes with hydrochloride gas. (v) Black metallic oxide which dissolves in nitric acid to give greenish blue solution. (d) State one observation for each of the following: (i) Hydrogen chloride gas is passed through a solution of sodium thiosuphate. (ii) Zinc reacts with dilute sulphuric acid (iii) When crystals of copper nitrate are heated in a test tube. (iv) When the gaseous product obtained by dehydration of ethyl alcohol is passed through bromine water. (v) When moist starch iodide paper is introduced into chlorine gas. 2 ICSE (Grade : X) | CHEMISTRY (SCIENCE Paper-II) | Pre Board Exam-II [5] (e) (f) (g) Match the options from A to E with the statements (i) to (v): [5] A. Action of water on CaC 2 (i) Alkanes B. Unsaturated hydrocarbon (ii) Substitution reaction C. Saturated hydrocarbon (iii) Addition reaction D. Wurtz reaction (iv) Alkyne E. Dehydration of alcohols (v) Alkene Write the IUPAC name of the following : [5] Write the balanced equations for the following reactions. (i) Heptane is subjected to strong heat is the absence of air. (ii) Reaction of chlorine with excess of ammonia. (iii) Catalytic oxidation of ammonia by oxygen (air). (iv) Ethanol to chloroethane. (v) Decomposition of urea equation. (h) [5] (a) When KClO3 is heated in presence of MnO2 ( as a catalyst) O2 is evolved.[K=39,Cl=35.5,O=16] 2KClO3 2KCl + 3O2 [3] (i) At STP calculate the mass of KClO 3 that is required to produce 6.72 L of O 2 . (ii) Find out the number of moles of oxygen present in the above volume and also the number of molecules. (b) Calculate the volume at STP that is occupied by 0.01 mole of CO2.[C=12,O=16] [2] SECTION B (40 MARKS) (Attempt any four questions from this section.) QUESTION 2: (a) Give reasons for the following: (i) Acetylene is more reactive than ethane. (ii) Hydrocarbons are excellent fuel. 3 ICSE (Grade : X) | CHEMISTRY (SCIENCE Paper-II) | Pre Board Exam-II [5] (b) (c) (iii) Sulphuric acid is called as kind of chemicals. (iv) Dry HCl gas not change the colour of the dry blue litmus paper. (v) Concentrated nitric acid is not used in the preparation of HCl. Draw the branched structural formula of (i) methoxy methane (iii) 3-methylbutan-1-ene (ii) 2-methylpropan-1-ol Define the following: (i) Catenation [3] [2] (ii) Pyrolysis Question 3: (a) Answer the following questions: (b) (i) For preparing fertilizers, explosives, dyes and drugs. (ii) Alcohol used in thermometer. (iii) Used for artificial ripening and preservative of fruit. (iv) Name of the acid which is used as a vinegar and for making pickles. (v) Write the name of acid used as a cleaning iron sheets before galvanization. (i) Which of the reaction take place between chlorine and ethane to form mono-chloroethane? [5] [5] (ii) Draw the structural formula of Propanoic acid. (iii) Write one test to confirm hydrochloric acid. (iv) Calculate the percentage of iron in iron (II) oxide. (Fe2O3 ) [ O=16, Fe=56] (v) Why does the pure nitric acid take on a yellow colour when exposed to light? Question 4: (a) The following statements are correct only under certain conditions. Rewrite each statement including appropriate conditions underlines in your answer. [5] (i) Hydrogen chloride gas is a covalent compound. (ii) Ammonia turns red litmus to blue. (iii) Sulphuric acid is least volatile acid. 4 ICSE (Grade : X) | CHEMISTRY (SCIENCE Paper-II) | Pre Board Exam-II (b) (iv) Magnesium reacts with nitrogen to form magnesium nitride. (v) Hydrogen chloride gas is soluble in water. Name the organic compound prepared by each of the following reactions. (i) (ii) [5] C2H5Br + alc. KOH C2H5OH + 2[O] (iii) HC = CH + O3 (iv) CH2 = CH 2 + H2O (v) CH3COOH + NaHCO3 Question 5: (a) The following questions are with the reference to the preparation of ammonia. (i) [5] What are the general methods of preparation of ammonia and give example for each? (b) (c) (ii) How can ammonia be liquefied? (iii) How does solubility of ammonia vary with temperature? (iv) What is the effect of inhaling ammonia? State the conditions required for the following reaction to take place. [3] (i) Catalytic oxidation of ammonia to nitric oxide. (ii) Preparation of ethyne from ethylene dibromide. (iii) Any two conditions for the conversion of sulphur dioxide to sulphur trioxide. What volume of oxygen is required to burn completely a mixture of 22.4 dm3 of methane and 11.2dm3 of hydrogen into carbon dioxide and stream ? [Assume that all volume are measured at STP] CH4 +2O2 CO2 + 2H2O 2H2 + O2 2H2O 5 ICSE (Grade : X) | CHEMISTRY (SCIENCE Paper-II) | Pre Board Exam-II [2] Question 6: (a) (b) The given figure shows the laboratory preparation of nitric acid. (i) Write the reactants used in preparation of nitric acid. (ii) Write the balanced equation for the above preparation. (iii) What are the conditions required for this preparation? (iv) What two precautions should be taken during this preparation? (v) How yellow colour of nitric acid can be removed. Write the name of organic compounds. [5] (i) Tetrahedral molecule. (ii) A carboxylic acid containing 2 carbon atoms. (iii) Third member of alcohol series. (iv) First member of ketone series. (v) First member of homologous series with general formula C nH2n. Question 7: (a) State one important use of the following: [2] (i) Acetic acid (ii) Methane (iii) Ethane (iv) Ethyne (b) Why sulphuric acid is not prepared directly from sulphur dioxide. [1] (c) Calculate the moles of 10g of sodium .[Na= 23] [1] (d) What happens when nitric acid falls on the skin and give reason for the same. [1] (e) Why freshly prepared ferrous sulphate is used to test nitrate. 6 ICSE (Grade : X) | CHEMISTRY (SCIENCE Paper-II) | Pre Board Exam-II [1] (f) Draw different isomers having the following molecular formula: (i) (g) C4H6 (position) (ii) C6H14 (chain) Write only chemical equations for the reaction of ethanoic acid with the following. (i) Phosphorus pentoxide (ii) [2] Magnesium 7 ICSE (Grade : X) | CHEMISTRY (SCIENCE Paper-II) | Pre Board Exam-II [2]
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