Candidates Name :______________________________________________________ Stream: _________________________________________________________________ 545/1 Chemistry Paper 1 Apr, 2026 2¹/2 hours TAIBAH INTERNATIONAL SCHOOL TEST 2 EXAMINATION S.5 CHEMISTRY 2¹/2 HOURS INSTRUCTIONS TO CANDIDATES »This examination paper consists of two sections: A and B »It has six examination items. »Section A has two compulsory items. Responses to section A must be written in the spaces provided »Section B has two parts; I and II. Respond to only one item from each part. »Responses to Section B must be written in the answer booklet(s) provided. »Respond to four items in all. »Responses to each item in section B should start from a fresh page. »Any additional item(s) responded to will not be scored.Item No. ScoreScorers’ Initials 1 2 ____(3/4) ____(5/6) Total Weighed scoreFor Scorers’ Use Only Turn OverTAIBAH INTERNATIONAL SCHOOLExodus Publishers 0788060585 www.exoduspublishers.org SECTION A ATTEMPT all ITEMS IN THIS SECTION. Item 1 A water treatment laboratory in Jinja is responsible for monitoring the quality of chemicals used in purification processes. One of the chemicals used is hydrochloric acid (HCl), but its exact concentration is unknown and must be determined before use. A laboratory technician decides to standardise the acid using a primary standard, anhydrous sodium carbonate (Na₂CO₃). The technician carefully weighs 1.50 g of anhydrous sodium carbonate, dissolves it in distilled water, and makes the solution up to 250 cm³ in a volumetric flask. He then pipettes 20.0 cm³ of this solution into a conical flask and titrates it with the hydrochloric acid using methyl orange indicator. The average volume of hydrochloric acid required for complete neutralisation is found to be 27.50 cm³. Task. As a chemistry student, use your knowledge to assist the laboratory technician. (a). Analyse the experimental setup and: (i). justify why anhydrous sodium carbonate is suitable as a primary standard (ii). formulate a balanced …