Formatting page ...
SACRED HEART CONVENT SCHOOL PRE BOARD EXAMINATION 2023- 24 SUBJECT CHEMISTRY CLASS X Time -2hrs Total marks 80 SECTION - A [Answer all questions from this section] Question 1: Choose the appropriate answer from the following options A, B, C and D: [15] i) The main ore used in the extraction of aluminium is A) Haematite B) Bauxite c) Calamine D) Cryolite ii) During the electrolysis of acidified copper sulphate solution with platinum electrodes, the colour of the electrolyte A)remains same B) fades away C) becomes darker D) first becomes dark and then fades away. iii) Carboxylic acid and alcohol combine to form A)amide B) ketone C) aldehyde D) ester iv) To increase the pH value of neutral solution, we should add (a) an alkali (b) an acid salt. (c) an acid. (d) a salt The second last element in the 3rd period of the modern periodic table is A)Fluorine C) Iodine D) Bromine B) Chlorine v)A compound X is heated in a test tube with alkali produces a pungent smell gas which turns red litmus solution into blue. Which of the following could compound X be? A)zinc sulphate B) copper sulphate C) ammonium sulphate D) ferrous sulphate vii) The atomic number of the elements A, B, C and D are 6, 11, 13 and 17. Which two elements combine to form a covalent compound? A)B and C B) A and B C) A and C D) A and D viii) Two neighbours of a homologousseries differ by: (a) CH (b) CH2 (c) CH3 (d)CH4 ix) The functional group of ethanol is ____________. A) OH B) CHO C) COOH x) D) >C = O Carbon dioxide and sulphur dioxide gas can be distinguished by using A)moist blue litmus B) lime water C) lead acetate solution D) acidified K2Cr2O7 solution xi) The molecular formula of glucose is C6H12O6. The empirical formula of the compound is: A) CHO B) C2H2O2 C) CH2O D) C2HO2 xii) When excess ammonium hydroxide solution is mixed with copper sulphate solution in a test tube, what do you observe in the substance present in the test tube? A) dirty green precipitate B) deep blue solution C) colourlesssolution D) pale blue precipitate xiii) The catalyst used in Haber s process is A) vanadium pent oxide B) platinum xiv) Alkenes undergo A) substitution reaction C) neutralisation reaction C) nickel D) finely divided iron B) addition reaction D) displacement reaction xv) The reason for using Aluminium in the alloy Duralumin is : A) aluminium is brittle B) aluminium gives strength C) aluminium brings lightness D) aluminium lowers the boiling point Question 2: i) The diagram shows an apparatus for the laboratory preparation of hydrogen chloride gas. [5] a) b) c) d) e) Identify A and B Write the equation for the reaction. How would you check whether or not the gas jar is filled with hydrogen chloride? Name the method used to collect hydrogen chloride gas. What does the method of collection tell you about the density of hydrogen chloride? ii) Complete the following by choosing the correct answers from the bracket: [5] a) Organic compounds containing carbon carbon triple bond are called _________.(alkene / alkyne) b) Ammonia gas is dried by _________ (Conc. H2SO4 / CaO ) c) Nitric acid is a strong __________ (oxidising / reducing) agent; therefore, it does not liberate hydrogen on reaction with metals. d) Concentrated sulphuric acid converts ethanol to____________ ( ethanal / ethene ) as it is a dehydrating agent. e) A colourless gas which turns lead acetate paper silvery black is ____________. ( sulphur dioxide / hydrogen sulphide) iii) Match the following Column A with Column B. Column A a. Roasting b. Carbon tetrachloride c. Sodium chloride d. Stainless steel e. Calcination [5] Coulmn B 1. Electrovalent compound 2. Surgical instrument 3. Carbonate ore 4. Sulphide ore 5. Covalent compound iv) Name or Identify the following: [5] a) The energy required to remove an electron from a neutral isolated gaseous atom. b) A homogenous mixture of two or more metals or a metal and a non-metal in a definite proportion in their molten state c) The salt formed by the complete replacement of the ionisable hydrogen atoms of an acid by a metallic ion. d) Equal volume of all gases under similar conditions of temperature and pressure contain the same number of molecules. e) Compounds having the same molecular formula but different structural formula. v) a) Draw the structural formula for the following compounds: [3] 1. Ethanoic acid 2. But - 2- ene 3. 2 methyl propane b) Write the IUPAC name for the following compounds: 1. CH3 - CHO 2.CH2 = CH CHCl CH2- CH3 [2] SECTION B (40marks) [Answer any four questions from this section] Question 3: a) With reference to the first three periods of the modern periodic table answer the following questions: [3] i) Name the element which has the highest ionization potential. ii) How many electrons are present in the valence shell of an element with atomic number 15? iii) Identify the noble gas present in period 3. b) Give reasons for the following: [3] i) Ionic compounds have high melting and boiling point. ii) Molten sodium chloride conducts electricity. iii) Noble gases have zero electron affinity. c) Draw the electron dot diagram for the formation of hydronium ion. [2] d) An atom X has three electrons more than the noble gas configuration. [2] i) What type of ion will it form? ii) Write the formula of its sulphate. Question 4: a) Select from the list given below ( A to C), one substance in each case which matches the description given in parts (i) to ( iii). [3] A. Iron (III) chloride B. Lead (II) chloride C. Sodium chloride i) A compound whose aqueous solution is neutral in nature. ii)A compound which is deliquescent. iii) A compound which is insoluble in cold water but soluble in hot water. b) Give reason for the following statements [3marks] i)An all glass apparatus is used for the preparation of nitric acid. ii)Alkanes are less reactive than alkenes. iii)Nitrides are less preferred for the preparation of ammonia. c) Mr Raju wants to electroplate his key chain with silver to prevent it from rusting. For thiselectroplating: (3marks) i) Name the electrolyte used. ii) Name the electrode formed by the article to be electroplated. iii) Give the reaction at the anode. d) An aqueous solution containing OH1-, NO31-, SO42- ions. Name the ion which will discharge at the anode. [1] Question 5: a) Answer the following questions with respect to laboratory preparation of ammonia : [3 marks] I)Write balanced chemical equation for the preparation using ammonium salt ii)How is ammonia gas collected? iii)How can it be ensured that the collection jar is full of ammonia gas? b)Write the balanced equation for the following: [3] i) Action of warm water on calcium nitride ii) Oxidation of copper with concentrated nitric acid. iii) Action of aqueous KOH on bromoethane c) X [2, 8, 7] and Y [2, 8, 2] are two elements. Using this information complete the following: [3] (I) __________ is the metallic element.(ii) Metal atoms tend to have a maximum of __________ electrons in the outermost shell.(iii) ___________ is the reducing agent. d) On adding concentrated sulphuric acid to salt A , a colourless gas which fumes in moist air evolves and the gas gives dense white fumes with ammonium hydroxide. Name the anion present in the salt A . [1] Question 6: a) In the electrolytic reduction of pure alumina by Hall Heroult s process. [3] I)Write the cathode reaction. ii) Write the function of cryolite. iii)Why is powdered coke sprinkled on top of the electrolyte? b)Copy and complete the table relating to an important industrial process. [3] Name of the process Contact process Inputs Catalyst Equation for catalyzed reaction Output Sulphur dioxide + Oxygen (i) (ii) (iii) c)What property of Sulphuric acid is exhibited in each of the following cases: [2] (i) In the preparation of HCl gas when it reacts with Sodium chloride. (ii) When conc. Sulphuric acid reacts with Copper to produce Sulphur dioxide gas d)(I)State wether the following statements are TRUE or FALSE. Justify your answer. [2] i)In an electrovalent compound, the cation attains the electronic configuration of the noble gas that comes after it in the periodic table.ii)In the formation of a compound PQ2, atom P gives one electron to each atom of Q. The compound PQ2 is a good conductor of electricity. Question 7: a) In the laboratory preparation of nitric acid: [2] i) Name the reactants a liquid (A) and the solid (B) used. ii) Write an equation to show how nitric acid undergoes decomposition. b) Name the gas evolved in the following:[2]i) Dilute nitric acid is added with copper. ii) Ammonia gas is burnt in air c) Identify the cation presents in the salt X and Y : [2] i) To the salt X calcium hydroxide solution is added and then the mixture is heated. A pungent smelling gas which turns moist red litmus paper blue is evolved. ii) NaOH solution is added to the salt solution Y reddish brown precipitate is formed. d)Name the alloy which is made up of:. [2] (a) Copper, Zinc and Tin (b) Lead and Tin e)Rani wants to prove that ammonia is a reducing agent. To demonstrate this, she passes ammonia gas over heated copper oxide. What will she observe?Write a balanced chemical equation for the above reaction. [2] Question 8: a) Copy and complete the following reactions: [2] i)C2H5COONa + NaOHCaO ii) CaC2 + 2H2O b) Give a suitable name / term for the following: [4] i) A reaction in which hydrogen of an alkane is replaced by a halogen. ii) Ice like crystals formed on cooling an anhydrous acetic acid sufficiently. iii) A bond formed between two atoms by sharing of a pair of electrons, with both electrons being provided by the same atom. iv) The gaseous hydrocarbon commonly used for welding purposes. c) Write balanced equation for the preparation of the following : [2] (i) Action of alcoholic KOH on bromoethane (ii)) complete combustion of ethane d) i) Explain the term esterification. ii)Define catenation. [2]
|
