CCE PF REVISED O %lo ÆË v ÃO y Æ fio» flms ÿ,» fl Ê«fiÀ M, ÊMV fl 560 003 KARNATAKA SECONDARY EDUCATION EXAMINATION BOARD, MALLESWARAM, BANGALE 560 003 G È.G È.G È.. Æ fioê,» ^È% / HØ È 09 S. S. L. C. EXAMINATION, MARCH/APRIL, 09» D} V fl MO : 0. 04. 09 ] MODEL ANSWERS MOÊfi} MSÊ : 83-E (Chem.) Date : 0. 04. 09 ] CODE NO. : 83-E (Chem.) Œ æ fl : e k Subject : SCIENCE ( æ fl À apple / Chemistry ) ( Ê Æ p O» fl / New Syllabus ) ( S W @ % / Private Fresh ) C (BMW«ŒÈ Œ M} / English Version ) [ V Œ r @MO V fl : 00. The functional groups present in propanol and propanal respectively are (A) OH and CHO (B) OH and COOH (C) CHO and COOH (D) CHO and CO [ Max. Marks : 00 (A) OH and CHO 5. The chemical equation that represents neutralization reaction among the following is (A) BaCl + H Ba + HCl (B) MnO + 4 HCl MnCl + H O + Cl (C) NaOH + H Na + H O (D) AgNO 3 + HCl AgCl + HNO 3 (C) NaOH + H Na + H O [ Turn over
83-E (Chem.) CCE PF 8. The electronic configuration of element X is, 8, 8, and the electronic configuration of element Y is, 8, 7. Then the type of bond formed between these two elements is (A) covalent bond (B) hydrogen bond (C) metallic bond (D) ionic bond (D) ionic bond. Name the acid present in the stinging hair of nettle leaves. Methanoic acid 5. What is roasting in metallurgy? Heating of metallic ores strongly in the presence of excess air. 0. Name the brown fumes liberated when lead nitrate is heated. Write the balanced chemical equation for this reaction. Nitrogen dioxide ( NO ) Pb ( NO 3 ) PbO + 4NO + O 3. What are structural isomers? Name the first member of alkanes that shows structural isomerism. Compounds with identical molecular formula but different structures are called structural isomers Butane or C 4 H 0 5. Draw the diagram of arrangement of apparatus used to show the reaction of zinc granules with dilute sulphuric acid and testing hydrogen gas by burning. Label the following parts. Soap solution Delivery tube.
CCE PF 3 83-E (Chem.) Delivery tube Soap solution + + 9. Draw the diagram of the apparatus used in the electrolysis of water. Label the following parts. Graphite rod Cathode. Graphite rod Cathode 6 V ( Cathode can be labelled by connecting graphite rod to the negative terminal of the battery ) + + [ Turn over
83-E (Chem.) 4 CCE PF 3. There is no change in the colour of red litmus and blue litmus paper when introduced into an aqueous solution of sodium chloride. After passing direct current through the same solution, red litmus changes to blue colour. Which product is responsible for this change? Mention any two uses of this product. Sodium hydroxide / NaOH. De-greasing metals (iii) Soaps and detergents Paper making (iv) Artificial fibres. ( Any two ) 36. Write the structural formulae of the following compounds : Cyclohexane Chloroethane.
CCE PF 5 83-E (Chem.) 39. Draw the diagram of apparatus used in refining of copper from copper sulphate solution. Label the following parts. Anode Acidified copper sulphate solution. + Anode Acidified copper sulphate solution + + 4. Write the balanced chemical equations for the following reactions. Red hot iron reacts with steam Magnesium reacts with dilute hydrochloric acid. 3Fe + 4H O Fe 3 O 4 + 4H Mg + HCl MgCl + H 46. Write the differences between saturated and unsaturated hydrocarbons. Write the molecular formula and structural formula of an alkene having five carbon atoms. Carbon atom does not form C 4 anion and How can ethanol be converted into ethanoic acid? C 4 + cation. Why? [ Turn over
83-E (Chem.) 6 CCE PF Saturated hydrocarbons : In carbon compounds, carbon atoms are satisfied by a single bond between them These compounds are normally not very reactive. Unsaturated hydrocarbons : In carbon compounds, carbon atoms have double or triple bonds between them They are more reactive than the saturated carbon compounds. C 5 H 0 3 Carbon could gain four electrons. But it would be difficult for the nucleus with six protons to hold on to ten electrons, that is four extra electrons. It could lose four electrons but it would require a large amount of energy to remove four electrons leaving behind a carbon cation with six protons in its nucleus holding on to just two electrons. Alkaline potassium permanganate or acidified potassium dichromate is added to ethyl alcohol. When it is heated it oxidises to form ethanoic acid. 3 CH 3 CH OH CH 3 COOH
CCE PF 7 83-E (Chem.) 49. Observe the given table and answer the following question : Elements A B C D E Atomic number 4 7 9 Identify the two elements that belong to the same period and the two elements that belong to the same group. Give reason for your conclusion. Element B and element D are in same period because their atoms have two shells. Element A and element E are in the same group because their outermost shell has one electron. 3 5. Give reason. Ionic compounds in solid state do not conduct electricity, whereas in molten state are good conductors of electricity. (iii) Silver articles when exposed to air gradually turn blackish. Chemical reaction does not take place when copper is added to iron sulphate solution. Give reason. (iii) Alloys of iron are more useful when compared to pure iron. Copper loses its brown layer gradually when exposed to air. Aluminium oxide is called amphoteric oxide. [ Turn over
83-E (Chem.) 8 CCE PF In the solid state, ionic compounds do not conduct electricity because movement of ions in the solid is not possible due to their rigid structure, because of the strong force of attraction between the positive and negative ions. In molten state electrostatic forces of attraction between the oppositely charged ions are overcome due to the heat. Thus the ions move freely and conduct electricity. Silver reacts with sulphur in the air to form a coating of silver sulphide. (iii) Reactivity of copper is less than that of iron. 4 Pure ions is very soft Stretches easily when hot. Alloys are more hard. The properties of iron metal can be changed if it is mixed with other substance. (iii) Copper reacts with moist carbon dioxide in the air and slowly loses its shiny brown surface and gains a green coat. Aluminium oxide ( Al O 3 ) reacts with both acids as well as bases to produce salt and water. 4