Formatting page ...
ST. MARY S SCHOOL (ICSE), MAZAGAON , MUMBAI. CLASS:10 PRELIM EXAMS DATE:05/01/2018 CHEMISTRY MARKS:80 TIME:2 HRS SECTION I ( 40 MARKS ) Attempt all questions from this section. Q1. a. i) A: B: Choose the correct answer from the options given below : C: D: Which of the following is generally true ? Atomic size increases from left to right across a period. Number of valence electrons decreases from left to right across a period. Electron affinity increases down a group. Ionisation potential decreases down a group. ii) A: B: C: D: Conversion of bromoethane to ethene is an example of : Dehydrogenation Dehydrohalogenation Decarboxylation Dehydration iii) A: B: C: D: Which of the following acid does not form an acid salt ? H3PO4 CH3COOH H2SO4 H2SO3 iv) Concentrated sulphuric acid is used as a reactant in the preparation of HCl gas as it is a : Strong oxidizing agent Drying agent Dehydrating agent Non volatile acid. A: B: C: D: (5) v) A: B: C: D: The salt which undergoes thermal dissociation on heating is : NH4Cl NH4NO3 NH4NO2 (NH4)2SO4 b. Write balanced chemical equations for each of the following: i) ii) iii) iv) v) Action of dilute sulphuric acid on potassium carbonate. Reaction of calcium nitride with warm water. Prepare methane from sodium ethanoate. Action of concentrated nitric acid on carbon. Reaction of nitre with concentrated sulphuric acid. c. State your observation when : i) iii) iv) v) Acetylene is passed through ammoniacal cuprous chloride solution Carbon dioxide gas is passed through potassium permanganate solution. Ammonium hydroxide is added to ferrous chloride solution. Excess ammonia reacts with chlorine gas. Manganese dioxide reacts with concentrated hydrochloric acid. d. State the property of the underlined substances: i) Slaked lime is preferred over other caustic alkalis in the preparation of ammonia. Quicklime is not used to dry hydrogen chloride gas. Concentrated sulphuric acid is used to convert ethanol to ethene. Zinc is alloyed with copper in the manufacture of Brass. Aluminium is used in paints. ii) ii) iii) iv) v) e.i) During electrorefining of copper using copper sulphate solution, 1. What is the anode made of ? (5 ) (5 ) (5 ) (3 ) 2. 3. Name the ions that migrate to the anode but are not discharged. Give the reaction at the anode. ii) Select the method of preparation, for the following salts: ( Synthesis, Precipitation, Neutralisation, Displacement ) 1. 2. Sodium sulphate. Lead sulphate. f. The equation for the action of heat on calcium nitrate is as (5 follows: ) 2Ca(NO3)2 2CaO + 4NO2 + O2 (Ca=40, N=14, O=16) How many moles of NO2 are produced when 1 mole of Ca(NO 3)2 decomposes ? What volume of O2 at stp will be produced on heating 65.6 g of Ca(NO3)2 ? Find the percentage composition of Ca in 2 moles of Ca(NO3)2 . i) ii) iii) g.i) Write the IUPAC names of the following: 1 H H | | H C CO C H | | H H 2 H H H O | | | || H C C C C H | | | H H H 3 H C=C H | | Br Br ii) 1 2 State the composition of the following alloys: Bronze Duralumin (2 ) (5 ) h. i) ii) iii) iv) v) Fill in the blanks with the correct option and rewrite the (5 statements. ) ________ ( Electronegativity/ Electron affinity) is the tendency of an atom to attract electrons to itself when combined in a compound. Ferric chloride salt is stored in air tight container as it is a/an ______ ( deliquescent/ efflorescent ) salt. The size of the ______ ( cation/anion ) is larger than the parent atom. CH4 is a covalent compound having only ______(ions/molecules) Phenolphthalein does not change colour when passed through a solution of ______ ( ammonia/ hydrogen chloride ) gas. SECTION II ( 40 MARKS ) Attempt any four questions. Q2 a. . i) ii) State the inference from the following observations. A salt X reacts with barium chloride solution to give a white precipitate insoluble in dilute hydrochloric acid. State the anion in X . A salt Y on heating with sodium hydroxide gives a gas which turns nessler s reagent brown. State the cation in Y . b. Give a chemical test to distinguish between : i) ii) Dilute HCl and dilute HNO3 ZnSO3 and ZnS c. Give reasons : i) Concentrated solution of sodium hydroxide is used to purify bauxite. The graphite anodes are continuously replaced during electrolysis of alumina. ii) (2 ) (2 ) (3 ) iii) Aluminium is used in thermite welding. d. In the extraction of aluminium, i) Besides Alumina, another aluminium compound is added to the electrolyte. Write its formula. Name the anions present in the electrolyte mixture. Give the reaction taking place at the cathode. ii) iii) Q3 a. . During the electrolysis of acidified water, i) ii) Why is dilute sulphuric acid added to pure water ? Give the reactions taking place at the cathode and anode. b. Select the ion in each case: i) The cation discharged at the cathode most readily. ( Fe2+ , Ag1+ , H1+ , Cu2+ ) The anion discharged at the anode with most difficulty. ( Br1- , Cl1- , OH1- , SO42- ) ii) c. Write balanced equations to prepare the following salts. i) ii) iii) Ferric chloride from iron. Lead chloride using dilute hydrochloric acid. Calcium carbonate from calcium chloride. c. From the metals- Cu, Fe, Mg , Zn , select one metal in each case. i) ii) Reacts reversibly with steam. Its hydroxide reacts with both acids and alkalis. Q4 a. . i) ii) Give the structural formula of: Butanoic acid 3-methyl but-1-yne (3 ) (3 ) (2 ) (3 ) (2 ) (2 ) (3 ) b. Give balanced equations for the following reactions: i) ii) iii) 1,2, dibromoethane is boiled with alcoholic potassium hydroxide. Hydrolysis of chloroethane with aqueous sodium hydroxide. Reaction of ethanoic acid with ammonium hydroxide. c. Draw an electron dot diagram of the hydronium ion and state the (2 type of bonding. ) d.i ) State which of the following : CCl4 , CuCl2 , Na2CO3 is a non- (3 conductor of electricity ? ) Name a molecule that contains a triple covalent bond ? Na+ Na. State whether the cation is reduced or oxidized to neutral atom. ii) iii) Q5 a. LPG has 60% propane and 40% butane.10 litres of this mixture is (3 burnt. Calculate the volume of carbon dioxide added to the ) atmosphere. C3H8 + 5O2 3CO2 + 4H2O 2C4H10 + 13O2 8CO2 + 10H2O b. Calculate the number of gram molecules in 22.2 g of calcium (2 chloride. ( Ca = 40 , Cl = 35.5 ) ) c. Fill in the blanks and rewrite the complete statement by (3 underlining the blanks. ) i) iii) Properties of elements are periodic function of their _________ ( atomic number/ atomic mass number ) Elements in a group have similar chemical properties as they have the same number of _______ ( valence electrons/ orbits) Non-metallic character_____(increases/decreases) down a group d. Give balanced chemical equations to prove that: i) ii) Dilute hydrochloric acid contains hydrogen. Cold dilute nitric acid is an oxidizing agent. ii) (2 ) Q6. a. Give balanced equations for the following conversions: ( A, B and C are three different acids.) A B Sodium thiosulphate Sulphur Sulphur dioxide |C Sulphuric acid (3) b. State your observation when : i) ii) iii) Ammonia burns in air. Concentrated sulphuric acid is added to hydrated copper sulphate. Ammonia is passed over heated cupric oxide. (3 ) c. In the Contact process , name the following : i) Catalyst used in the conversion of sulphur dioxide to sulphur trioxide. Acid diluted with water to form sulphuric acid. State the following: (2 ii) d. i) ii) One property common of ammonia and hydrogen chloride gas. One difference in the method of collection of ammonia and hydrogen chloride gas during their laboratory preparation. (2 ) )
|
