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ST. JOHN S UNIVERSAL SCHOOL CLASS: X DATE: 12/10/2020 FIRST PRELIMINARY EXAMINATION 2020 2021 CHEMISTRY MARKS: 80 TIMING: 2 Hours Answers to this paper must be written on a ruled sheet. First 15 minutes are to be spent in reading the question paper. The time given at the head of this paper is for writing the paper. The Answer Sheet should have the following details mentioned- Date, Full Name, Class & Division, Subject. The pages should be numbered appropriately. ____________________________________________________________________________________ This Paper comprises of two sections. Section I is compulsory. Attempt any 4 questions from section II. ____________________________________________________________________________________ Section I (40 marks) (Attempt all questions from this section) Question 1 (a) Choose the correct answer from the options given below: [5] (i) Which of the following is an example of an ionic bond: (A) Methane (B) Carbon tetra chloride (C) Water (D) Sodium oxide (ii) Concentrated nitric acid reacts with Sulphur and forms: (A) Phosphoric acid (B) Sulphuric acid (C) Sulphurous acid (D) Hydrochloric acid (iii) Which is a weak electrolyte? (A) Dil. HCl (C) Carbonic acid (B) NaOH (D) KCl (iv) A metal oxide which can react with acid as well as alkali : (A) Silver oxide (B) copper(II) oxide (C) Aluminium oxide (D) Calcium oxide (v) Which of the following gases turns acidified potassium dichromate green: (A) Sulphur dioxide (B) Carbon dioxide (C) Carbon monoxide (D) Chlorine (b) Identify the compound which matches the following description: [5] (i) A compound when heated with copper(II) oxide gives a reddish brown metal. (ii) Oxidised product formed when copper reacts with dilute nitric acid. (iii) An acid that forms curdy white precipitate with silver nitrate.
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