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SCIENCE PAPER 2 CHEMISTRY 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 on reading the Question Paper. The time given at the head of this paper is the time allowed for writing the answers. Section I is compulsory. Attempt any four questions from Section II. Section I (40 Marks) Answer all the questions Question 1 a) Name the following. i) The element with highest Electron affinity value. ii) The gas which gives brown precipitate with Nesseler s reagent. iii) The change that a cation undergoes at cathode during electrolysis. iv) The conversion of a metal sulphide into a metal oxide by heating in presence of air. v) A gas which has suffocating odour and turns acidified Potassium dichromate to clear green solution. b) Match the following. Example- vi-G Part-A Part-B i) A gas which turns lime water milky A) Nitrogen and has suffocating odour ii) It oxidizes a non metal to its acid B) Sulphur dioxide iii) The gas released when Ammonia is oxidized in the absence of catalyst C) Vapour density rd iv) The element which belongs to 3 D) Nitric acid period and has largest atomic size among the elements belong to the same period E) Fluorine v) The ratio between the mass of a gas F) Sodium and the mass of Hydrogen gas of the same volume c) Select the correct answers from the words given below: i) Which of the following has a triple bond in its molecule? A) Oxygen B) Nitrogen C) Hydrogen D) Chlorine ii) Which of the following is not true about Sulphuric acid? A) Oxidising agent B) dehydrating agent C) Volatile D) drying agent iii) A gas which is used as one of the reactants in the catalyzed oxidation in Ostwald s process: A) Nitric oxide B) Nitrogen dioxide C) Ammonia D) HCl iv) Carboxylic acid group A) CHO v) B) COOH C) CO D) O A strong electrolyte: A) undergoes complete dissociation B) undergoes partial dissociation C) contains ions and molecules D) does not contain ions d) Fill in the blanks:i) Atomic radius decreases across a period as the nuclear effect on the valence electrons _____________ (decreases/ increases). ii) Alkenes undergo _____________ (addition/substitution) reactions. iii) Conc. Sulphuric acid is used in the laboratory preparation of Nitric acid and Hydrochloric acid because it is __________ (less volatile/ stronger) than other two acids. iv) ___________ (Cryolite/ Haematite) is an ore of Iron. v) __________ (A.C/ D.C) current gives effective coating on the article in electroplating. e) Correct the following statements and rewrite. i) Nitrogen atom in Ammonia molecule contains two lone pairs of electrons. ii) Cryolite is added to Bauxite ore to remove impurities in Baeyer s process. iii) Hydration is the addition of Hydrogen atoms to an unsaturated hydrocarbon. iv) Silver nitrate is the electrolyte used in electroplating an article with Silver.s v) Dilute Sulphuric acid forms two types of salts as it is a strong acid. f) Select the correct answer from the list for the statements given. (Copper, Cu2+ , Ferric chloride, Metallic character, Al2O3, Ammonium chloride) i) The compound which involves coordinate covalent bonding. ii) A deliquescent salt. iii) An amphoteric substance. iv) The product at cathode in the electrolysis of Copper sulphate using Copper electrodes. v) The periodic property which increases down a group as the atomic size increases. g) i) Find the mass of A) 2 moles of Carbon dioxide B) 6.72 lit. of Nitrogen gas ii) Find the percentage of water in copper sulphate ctystals iii) A compound has Empirical formula CH2O, V.D is 60. Find its A) Molecular formula B) Relative Molecular Mass Atomic wt. H-1, C-12, N-14, O-16, S-32, Cu-64) h) Write balanced equations for the following. i) A CuO H2SO4 + Water ii) Obtain an insoluble salt using dil. Hydrochloric acid iii) Prepare Oxygen gas from a metal nitrate ( release of Nitrogen dioxide should not be involved) iv) Reduce Lead oxide to Lead. Section II (40 Marks) Answer any four of the following questions Question 2 a) i) Which of the following elements has largest atom. Cl, Na, K, Si, Al ii) Arrange the following elements in the decreasing order of their Electron affinity values F, Br, Cl, I iii) Name the element which has the highest Ionization potential value. iv) Two elements A nad B belong to the same group and A is more electronegative than B. Compare their atomic sizes. b) i) Give reason why Neon has zero E.A value. ii) How does metallic character change with the increase in number of shells? iii) If an element P belongs to group IIA , then P loses/ gains electrons. c) i) X and Y are two elements having 2 and 7 valence electrons. State the nature of the bond between them and write the formula of that compound. ii) P is metal and Q is a non metal containing diatomic molecules. They combine to form P2Q3. Write balanced equation for the reaction. iii) An element X has 4 valence electrons and forms a covalent compound with Hydrogen. Draw the electron dot structure of that compound. Question 3 a) i) What is lone pair of electrons? State the consequence of having lone pair of electrons. ii) Give reason why ionic compounds have high melting point and boiling point. iii) Compare the conductivity of Carbon tetra chloride and molten Sodium chloride. b) i) A neutral solution will have pH value ___________ (1/13.5/7). ii) Name the salt formed when Sulphuric acid is neutralized partially with Sodium hydroxide. iii) A triacidic base which is insoluble in water c) Select the suitable method for the preparation of the following salts from A, B and C A: Precipitation B: Neutralization i) Sodium chloride ii) Ferric chloride iii) Lead sulphate C) Combination reaction Question 4 a) i) Name the compound which is deliquescent and used as a desiccating agent. ii) Which of the following ions will be discharged most easily Na+, Cu2+, Ag+ , Al3+ iii) Which ion is reduced during electrolysis of acidified water? b) i) Compare Acetic acid and Sulphuric acid in terms of the particles present in them. ii) Write balanced cathode reaction in the electrolysis of Copper sulphate using Copper electrodes. iii) Give reason why Graphite is preferred as anode over Iron in the electrolysis of fused Lead bromide. c) The given diagram demonstrates the electroplating an article with Nickel. i) Name X and Y ii) Write reaction takes place at Anode iii) State any one precaution. Question 5 a) i) Find the volume of Oxygen required to burn 440 cc of Carbon monoxide into Carbon dioxide. ii) The following reaction is between Sodium sulphite and dilute Sulphuric acid Na2SO3 + H2SO4 Na2SO4 + H2O + SO2 If 2.8 lit of SO2 is to be prepared, find i) The mass of Sodium sulphite required ii) The number of moles of Sodium sulphate produced. iii) The number of moles of Sulphur dioxide produced in the above case. b) Name the following i) An ore of Aluminium used in the extraction of Aluminium metal. ii) An alloy containing Zinc and Copper as its component metals. iii) The metal used as reducing agent in thermite welding. c) Answer the following questions pertaining to the extraction of Aluminium. i) How can we reduce the fusion point of Alumina taken in Hall Heroult s process. ii) Write balanced cathode reaction. iii) Give reason why the electrolyte is covered with coke powder. Question 6 a) Differentiate the following pairs of compounds using a common reagent in each case. i) Sodium sulphite and Sodium sulphate ii) Dilute nitric acid and dilute Sulphuric acid b) Identify the salt in each of the following cases: i) A salt X gives lilac flame in flame test and used in the laboratory preparation of Nitric acid. ii) A salt Y on heating leaves a black residue and its solution gives a pale blue precipitate with small amount of ammonium hydroxide. c) Write balanced equations for the reactions: i) Sodium thiosulphate with dilute Hydrochloric acid. ii) Oxidation of Conc. HCl using Pb3O4 d) State your observations when: i) Silver nitrate solution is added to dil. Hydrochloric acid. ii) Copper metal is added to Conc. Nitric acid. e) Give reason: i) Dilute Nitric acid is not used to prepare Hydrogen gas with metals. ii) Nitric acid prepared in the lab appears in yellow colour. Question7 a) State your observations when: i) Ammonia gas reacts with excess Chlorine gas ii) Conc. Sulphuric acid is added to Sugar crystals. b) Write balanced equations: i) Catalyzed oxidation in Contact process ii) Industrial preparation of Ammonia gas. iii) Preparation of Ethene from Ethyl halide. iv) Preperation of an ester using Ethanoic acid c) Write IUPAC names: d) Give branched structures of the following compounds i) Propanoic acid ii) 2 methyl 1- Butanol
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