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SECOND PRELIM EXAMINATION 2015-2016 CLASS: X DATE: 14/01/16 Subject: Chemistry Marks: 80 Dur : 2Hrs Section A (40 Marks) Attempt all the questions from this Section Q1 A Name the following 8 1. The electrolyte used to electroplate an article with silver. 2. The salt which on reaction with water produces ethyne gas. 3. A solid dehydrating agent. 4. A solution which on heating with calcium carbonate produces carbon dioxide gas. 5. The type of reaction which takes place when ethanol is converted to ethene. 6. An aqueous salt used for testing sulphate radical. 7. A coloured deliquescent salt. 8. The gas produced on heating sodium nitrate. 1. 2. 3. 4. 5. 6. ` B Choose the correct alternative 6 The formation of ethene from ethyl chloride is an example of a) Substitution b) Dehydration c) Dehydrohalogenation d) Addition 0.80g of CH4 contains a) 2 Moles b) 0.5 moles c) 0.05 moles d) 0.005 moles Chemically rust is a) Fe3O4 b) Fe2O3 c) Fe3O4.xH2O d) Fe2O3.xH2O The organic compound mixed with ethanol to make it spurious a) Methanoic acid b) Methanal c) Methanol d) Ethanoic acid A nitrate which produces laughing gas on decomposition a) Ammonium nitrate b) Calcium nitrate c) Sodium nitrate d) Ferric nitrate The metal whose hydroxide does not decomposes on heating but its nitrate decomposes on heating a) Sodium b) Calcium c) Iron d) Aluminium C Give observations for the following 1. Ethyne is added to ammonical cuprous chloride solution. 2. Sodium hydroxide is added to lead nitrate in drops followed by excess. 3. Ammonia gas is oxidised. 4. A piece of sodium is dropped in a test tube containing ethyl alcohol. 5. Carbon monoxide is passed over heated copper oxide. 6. Dilute sulphuric acid is added to ferrous sulphide. 6 D Give reasons for the following 5 1. Metal acts as a good reducing agent. 2. Copper is a good conductor of electricity but it is not an electrolyte. 3. Alkanes undergo substitution reaction, while alkenes undergo addition reaction. 4. The gas obtained when zinc reacts with dilute H2SO4 or concentrated H2SO4 are different. 5. To distinguish between dilute Nitric and dilute sulphuric acid, barium chloride solution can be used. Page 1 of 4 E 1. Write down the IUPAC names for the following Cl CH3 CH C CH2 CH3 4 2. Br O CH3 CH CH C CH3 CH3 3. Cl O CH3 CH CH C H CH2 CH3 4. OH CH3 CH3 CH CH CH2 CH CH3 CH3 F Solve the following 1. Find the percentage of Copper in hydrated Copper Sulphate. [Cu = 64; S = 32; O = 16: H = 1] 2 2. A gaseous compound of nitrogen and hydrogen contains 12.5% of H by mass. Find the molecular formula of the compound if its relative molecular mass is 37. [H = 1; N = 14] G Define the following 1. Homologous series 2. Ionisation potential H 2 Complete the following N2 + 3H2 B Fe 4 3 Dissolved in water under pressure A Solution C of CuSO4 is added Blue Precipitate Section B (40 Marks) Attempt Any Four questions from this Section Q2 A Write down the composition and use of the following alloy 1. Bronze 2. Duralumin B Complete the following table Page 2 of 4 4 4 Ag2O + HNO3 A + H2O + HCl B + HNO3 Excess of NH4OH C Give balanced equation for the formation of C from B C Write down balanced chemical reaction when 1. Copper reacts with concentrated nitric acid. 2. Ferric hydroxide with dilute nitric acid. Q3 2 A Two colourless liquid A and B react in presence of concentrated sulphuric acid forms a compound C, which has fruity smell. 3 1. Name the reaction. 2. Name compound C. 3. Write down reaction involved. 1. 2. 3. 4. B Write down the balanced equations to show the following conversions Acetic acid to methane. Ethyl chloride to ethene. Methane to methanal. Ethanol to diethyl ether. 5 C A Q4 Write down electron dot structure for the formation of Magnesium chloride 2 With reference to the extraction of Aluminium from its ore 1. Name the impurities present and how are they removed? 2. Write down the reactions involved in Baeyers process 3. Write down the reaction at cathode 1. 2. 3. 4. Q5 B Give a chemical test to distinguish between Sodium nitrate and sodium chloride. Copper sulphate and zinc sulphate. Ethane and ethene. Copper oxide and manganese di oxide. A With respect to electrolysis of acidified water 1. Which acid is added to water? Why? 2. Write down the ionic equation at cathode and anode. 3. Why electrolysis of acidulated water is called catalytic reaction? 2 3 1 4 4 B Compound A is bubbled through bromine water, dissolved in CCl 4 and the product is CH2Br CH2Br 4 CCl 4 A + Br2 CH2Br CH2Br 1. Draw the structural formula of A. 2. What type of reaction the compound A has undergone? 3. What do you observe? 4. Name the compound when steam reacts with A in presence of acid. Page 3 of 4 C Write down the balanced chemical equation when concentrated H 2SO4 reacts with the following 2 1. Hydrated copper sulphate 2. Carbon Q6 A The below table shows elements A, B, C, D and E with their atomic radius. Write the letter representing the element that shows the following properties 5 Elements A B C D E Atomic Radius 1. 2. 3. 4. 5. 0.88 0.70 0.64 0.77 1.55 Most electropositive element. Most non-metallic element. An element that has maximum tendency of gaining an electron. The element found to the extreme right of the periodic table. Arrange the elements in a proper sequence i.e. form most electronegative to the least electronegative. B Name the method used for the preparation of the following salts from list given 5 1. Sodium nitrate 2. Ferric chloride 3. Lead chloride 4. Zinc sulphate 5. Sodium hydrogen sulphate List a. Simple displacement b. Neutralisation c. Decomposition by acid d. Direct synthesis e. Double decomposition Q7 A Study the following flow chart 6 Gas A (excess) + ..... Sal Ammoniac + slaked lime + Cl2 Gas B (neutral) + .. + Red hot Mg Gas A + E Warm + H2O C (solid) 1. Identify B, C & E. 2. Write balanced equations for the formation of A, B & E. B Solve the following 3 Copper on reacting with concentrated H2SO4 produces copper sulphate. If 1.28g of Copper is to be converted to copper sulphate, then find [Cu = 64; S = 32; O = 16] 1. The weight of copper sulphate formed 2. The weight of acid required C State Gay Lussac s law ______________________ Page 4 of 4 1
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