APSACs WESTRIDGE III RAWALPINDI SAMPLE PAPER Subject: Chemistry (Objective) Marks: 12 Class: X Time: 20 Minutes Name: ______________________________ …………………………………………………………………………………………….. Note: Section – A is compulsory. All parts of this section are to be answered on the question paper itself. It should be completed in the first 20 minutes and Deleting / overwriting is not allowed. Do not use lead pencil. ………………………………………………………………………………………………. SECTION - A Q. 1: Insert the correct option i.e A/B/C/D in the empty box, provided opposite. Each part Carries one mark. (i) For removal of permanent hardness of water which compounds is used to convert calcium and magnesium ions into insoluble salts. (ii) (iii) (iv) (v) (vi) A. Washing soda B. Baking soda C. Caustic soda D. Lime stone Which of the following gases is used for extraction of metals from their ores? A. O₂ B. CO₂ C. CO D. N₂ The chemical change which indicates reduction is A. 2Cl¯ → Cl₂ B. H₂ → 2H+ C. Sn²+ → Sn D N₂ → NH₃ Iodized table salt is obtained by mixing — of potassium iodide by weight in sodium chloride. A 0.03% B. 0.02% C. 0.04% D. 0.01% Which of the following statements about silicon and its compound is incorrect A. Silicon is a semiconductor B. Silicon is a metalloid C. Formula of silicate is SiO₃ D. Silicon is an acidic oxide. Nitric acid reacts with hydrogen sulphide and oxidizes it to form A. 2H₂O + 2NO₂ +S B. H₂O + NO + S C. H₂ +NO₂ +SO₂ D H₂O + N + SO₂ (vii) The ore for extraction of iron in the blast furnace is A. Limonite B. Hematite C. (viii) (ix) (x) (xi) (xii) Magnetite D. Chalcopyrite Sulphuric acid is used in the manufacture of pigments A. BaSO₄ B. (NH₄)₂SO₄ C. Ca(H₂PO₄) D CaSO₄ The boiling point of Hydrochloric acid is. A. -87 C° B. -90 C° C. -98 C° D. -85 C° Steel is prepared in. A. Blast furnace B. Rotary kiln C. Fire furnace D. Electrical furnace -OH is the functional group of homologous series called. A. Alkyl halide B. Alcohols C. Alkenes D. Carboxylic acids Which of the fallowing will convert Fe³+ to Fe²+. A. C. [H] H₂O B. D. KMnO₄ K₂Cr₂O7 ________________XXXX________________ APSACs WESTRIDGE III RAWALPINDI SAMPLE PAPER Subject: Chemistry Marks: 53 Class: X Time: 2 Hrs 40 Min …………………………………………………………………………………………….. SECTION – B Marks: (3 x 11 = 33) Answer any ELEVEN parts from Section ’B’ and TWO from Section ‘C’ on the NOTE: separately provided answer book. Use supplementary answer sheet i.e. sheet – B if required. Write your answers neatly and legibly. …………………………………………….. Q.2: Attempt any ELEVEN parts. The answer to each part should not exceed 3 – 4 lines. (i) What is hard water which compounds are responsible for permanent hardness of water. (ii) (3) Milk of magnesia is used as a medicine to control the acidity of stomach. a. Write down the formula for medicine b. Write a balanced chemical equation for reaction of this medicine in the stomach (iii) (2) Complete the following equations. Also write the conditions. CO + (1) (3) → 2H₂ Vegetable oil + H₂ → 3H₂SO₄ + 2P → (iv) Chlorine is an oxidizing agent. Write down the equations of the reactions of Chlorine with a. Hot and concentrated solution of Caustic Soda (1) b. Aqueous potassium bromide (1) c. Aqueous Solution of ferrous chloride (1) (v) Consider the following equation. 2KMno₄ + 8H₂SO₄ +5Zn → K₂SO₄ +2MnSO₄+5ZnSO₄+ 8H₂O (vi) a. Define redox reaction. b. Which ion in the above reaction undergoes reduction. Calculate the Oxidation number of reduced atom. (2) Complete and balance the following equations. (3) CaC₂ + H₂O (vii) (1) → CO₂ + NaOH → SO₃ + H₂SO₄ → Sulphuric acid is produced in the industry by following reactions. S + O₂ → SO₂ + O₂ → SO₃ + H₂O → SO₂ 2SO₃ H₂SO₄ Starting with 200 gram of sulphur a How many kilo grams of SO₂ Can be obtained? (1) b. How many kilo grams of H₂SO₄ can be obtained? (2) (viii) a. In winter fish and other aquatic life continue to survive under frozen water explain why? b. Define water of crystallization. Give two examples of compound Containing water of crystallization. (ix) (1) a. What is activated charcoal. Write its uses. (2) b. What is a silicon chip? (1) (x) How atmospheric carbon dioxide and water react with bleaching powder. Explain with equation. (xi) (2) a. (3) Prove with the help of two reactions that nitric acid is an oxidizing agent. (2) (xii) b. What is equa ragia. give its composition. (1) a. What is the basic building unit of silica? (1) b. What is ovine. Write its chemical formula. (2) (xiii) The fallowing diagram represents the extraction of aluminium by electrolysis. a. Name a suitable compound that may be used in solution as an electrolyte for this reaction. (xiv) b. Write the equations for the reactions that occur at electrodes. (2) a. (1) Define an alloy. Why are they prepared b. write down the composition of brass bronze and steel. (xv) (1) (2) A hydrocarbon contains 10 carbon atoms. Give its molecular formula if it is a. Alkene b. Alkyne. b. Draw the possible isomers of pentane. ____________________XXXX____________________ (1) (2) SECTION – C Marks: (2x10=20) Note: Attempt any TWO questions. All questions carry equal marks. Q. 3: Sulphur is found in Free State under the earth’s surface. a. How it is extracted by frasch method b. sulphur can also be used as raw material for manufacture of (4) sulphuric acid by contact process. write down the steps involved in the process. (6) Q. 4: Copper is obtained from copper ore a. Describe froth flotation process for purification of copper ore. (4) b. Explain the refining of copper by electrolysis. (6) Describe the methods for removal of hardness of water. (6) Q. 5: a. b. Explain the preparation of bleaching powder in laboratary and on Industrial scale. ____________________XXXX____________________ (4)