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SHARADA MANDIR SCHOOL PRELIMINARY EXAM DEC 2023 STD : 10 CHEMISTRY MARKS : 80 TIME : 2HRS INSTRUCTIONS: 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 in reading the question paper. The time given at the head of this paper is the time allowed for writing the answers. Section A is compulsory. Attempt any four questions from Section B. The intended marks for questions or parts of questions are given in brackets. _____________________________________________________________________ Section A (40 Marks) (Attempt all questions from this section) Question 1: Complete the following statements by selecting the correct alternative from the choices given below each statement. (Write only the answers) [15] i) Carbon dioxide and sulphur dioxide gas can be distinguished by using: a) moist blue litmus paper b) lime water c) acidified potassium dichromate solution d) none of the above ii) The element which has greatest atomic radius is: a) Chlorine b) Magnesium c) Phosphorus d) Sodium iii) When a metal atom becomes an ion, it a) gains electrons and is reduced b) loses electrons and is oxidised c) gains electrons and is oxidised d) loses electrons and is reduced iv) The colour of Copper (II) hydroxide precipitate in ammonium hydroxide test is: a) Dirty green b) Gelatinous white c) Chalky white d) Pale blue v) The group which contains lithium is: a) Alkali Metals b) Alkaline earth metals c) Halogens d) Noble gases vi) The Gram molecular weight of carbon dioxide is : [C=12, O=16] a) 12g b) 28g c) 44g d) 22g vii) During the electrolysis of molten lead (II) bromide, which of the following takes place? a) Bromine gas is released at the cathode b) Lead is deposited at the anode c) Bromide ions gain electrons d) Lead metal is deposited at the cathode CONT D.... 1 PAGE 2 CHEMISTRY STD 10 viii) An example of an insoluble salt: a) KNO3 b) PbSO4 c) NaHSO4 d) Zn(NO3)2 ix) An ore of Aluminium is: a) Haematite b) Corundum c) Calamine d) Zinc blende x) Nitric acid is obtained using: a) Ostwald s process b) Haber s process c) Baeyer s process d) Hall Heroult s process xi) Action of conc. HCl on manganese dioxide evolves _________ gas. a) carbon dioxide b) nitrogen dioxide c) chlorine d) hydrogen sulphide xii) The catalyst used in the contact process is: a) nickel b) vanadium pentoxide c) finely divided iron d) iron (III) oxide xiii) Ammonia can be obtained by adding water to: a) Ammonium chloride b) Ammonium nitrite c) Magnesium nitrate d) Magnesium nitride xiv) The trivial name of ethyne is: a) Ethane b) Ethylene c) Ethene d) Acetylene xv) A particular solution contains molecules and ions of the solute so it is a: a) Weak acid b) Strong acid c) Strong base d) Salt solution Question 2: i) a) The diagram shows a simple arrangement of the fountain experiment: 1) Name the two gases you have studied which can be used in this experiment. 2) What is the common property demonstrated by this experiment? [5] CONT D.... 2 PAGE 3 CHEMISTRY STD 10 b) A solution of hydrogen chloride in water is prepared. The following substances are added to separate portions of the solution: [Copy and complete the table] Sr.No. Substances added 1 Calcium carbonate 2 Magnesium ribbon 3 Sodium sulphide Gas evolved ii) a) Draw the structural diagram for the following compounds. 1) Pent-1-yne 2) 2-methyl propane 3) Butan-1-ol [5] b) Give the IUPAC names of the following compounds. 1) 2) iii) Match the following column A with column B. Rewrite the correct pair. Column A Column B 1. Anode a. Cu (OH) Cl 2. Acid salt b. K2SO4 3. Cathode c. positively charged electrode 4. Basic salt d. KHSO4 5. Normal salt e. negatively charged electrode [5] iv) Complete the following by choosing answers from the brackets. [5] a) Melting and boiling points of covalent compounds are generally _________. (high, low) b) The volume occupied by one mole of gas at S.T.P is _________. (22.4L, 2.24L) c) The substance added to the ore to get rid of the impurities is called _____. (slag, flux) d) The method used to collect ammonia gas is ________. (downward displacement of air, upward displacement of air) e) The alkaline behaviour of liquor ammonia is due to the presence of ______ions. (hydroxyl, hydrogen) v) Do as directed. a) State your observation, when sodium hydroxide solution is added to the Zinc sulphate solution in excess. b) Give a balanced chemical equation for the laboratory preparation of hydrogen chloride. c) Name the catalyst used in the Haber s process. d) Define Catenation . e) State the colour of the residue, when zinc carbonate is heated strongly. [5] SECTION B (Attempt any four question) Question 3 i) Define the following terms. a) Atomic radius b) Ionisation potential [2] ii) a) What is meant by acidity of base? b) Is Zinc hydroxide a diacidic or triacidic base? [2] CONT D.... 3 PAGE 4 CHEMISTRY STD 10 iii) Copy and complete the following table. [3] General Formula Characteristic bond type IUPAC name of the first member of the series Type of reaction with chlorine CnH2n CnH2n+2 Single bond Methane Addition iv) Complete the following conversions marked A, B and C by giving balanced chemical equations. [3] A B C SODIUM ALUMINIUM BAUXITE ALUMINATE HYDROXIDE ALUMINA Question 4 i) Draw electron dot diagram for the formation of calcium oxide. ii) Complete the following equations and balance them. a) NH3 + O2 800 C b) NH3 + HCl [2] [2] Pt iii) Do as directed. [3] a) State one appropriate observation, when conc. nitric acid is added to copper metal. b) All glass apparatus is used in the laboratory preparation of nitric acid. Give a scientific reason. c) Give a property of nitric acid which allows it to react with carbon. iv) Find the empirical formula with the following percentage composition: Zn = 47.8%, Cl = 52.2% [Zn = 65, Cl = 35.5] Question 5 i) State the composition of the following alloys. a) Duralumin b) Stainless steel [3] [2] ii) What do you observe when sodium hydroxide solution is added in excess to: a) Calcium nitrate solution b) Ferrous sulphate solution [2] iii) Name the salt formed when dilute sulphuric acid is added to: a) Magnesium oxide b) Potassium sulphite c) Zinc sulphide [3] iv) Complete the following equations and balance them. a) CH3-COONa + NaOH [3] b) CaC2 + H2O c) C2H5-Br + KOH (aq.) CaO Question 6 i) The preparation of lead (II) sulphate from lead (II) carbonate is a two-step process. Write a balanced chemical equations for the same. [2] ii) State the trend of electron affinity across a period and give a reason for the same. [2] iii) What property of conc. sulphuric acid allows it to be used in the preparation of: a) sugar charcoal b) carbon dioxide from carbon c) acid salt and normal salt with an alkali [3] 4 CONT D.... PAGE 5 CHEMISTRY iv) Calculate: a) the number of moles present in 108 g of aluminium. [Al = 27] b) the mass of 0.5 mole of iron. [Fe = 56] c) the number of molecules in 32g of sulphur dioxide. [S= 32, O = 16] Question 7 i) Fill in the blanks. a) The pH value of a neutral solution is ____. b) The basicity of an acetic acid is ______. STD 10 [3] [2] ii) Draw the structural formula of: a) Methane b) Ammonia [2] iii) Answer the following questions. a) Give a confirmatory test for nitrate radical. b) Write a balanced chemical equation for the formation of oleum in the contact process. c) How will you differentiate between calcium ion and sodium ion using a flame test? [3] iv) Study the given figure and answer the questions that follow. a) Why is silica crucible used? b) Name the anode used. c) Write a balanced equation for the reaction at cathode. [3] Question 8 i) Arrange the following elements as directed. a) Ar, He, Ne (in increasing order of electron shells) b) N, Li, F, Be (in increasing order of electronegativity) [2] ii) Draw an electron dot diagram of: a) Water b) Hydronium [2] iii) Dry ammonia gas is passed over black substance as shown in the figure below: [3] a) Name the black substance A . b) Name the gas evolved B . c) Write a balanced chemical equation for the reaction. iv) Calcium hydroxide reacts with ammonium chloride to give ammonia according to the following equation: [3] Ca (OH)2 + 2NH4Cl CaCl2 + 2NH3 + 2H2O If 5.35 g of ammonium chloride are used. Calculate: a) the weight of calcium chloride formed. b) the volume at s.t.p of ammonia liberated. [H=1, N=14, O=16, Cl= 35.5, Ca=40] *****END ***** 5
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