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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
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