Neutralization Essay

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120 48. Classic chemistry experiments Titration of sodium hydroxide with hydrochloric acid Topic Acids and alkalis, neutralisation, formation of a soluble salt. Timing 45 min. Description 3 Students find the amount of acid required to neutralise 25 cm of sodium hydroxide. These volumes are reacted and sodium chloride is then crystallised. Apparatus and equipment (per group) 3 w 250 cm Conical flask 3 3 w 50 cm or 100 cm Burette w Burette stand 3 w One 25 cm or larger measuring cylinder. Chemicals (per group) –3 w Hydrochloric acid 1 mol dm w Sodium hydroxide 1 mol dm –3 (Corrosive) w Methyl orange. Teaching tips Demonstrate how to fill a burette and run out to the zero mark. With older groups, a pH sensor in the flask can monitor the pH change as the alkali is neutralised. Get the computer recording the pH sensor and allow the acid to drip at a steady rate as you swirl the flask. Data logging software will show the readings as a ‘classic’ strong acid-strong base titration curve where pH is on the y-axis and time (as a rough measure of the volume) is on the x-axis. Background theory Acids and alkali, salts. Safety Wear eye protection. Answers 1. Salt. 2. Hydrochloric acid + sodium hydroxide → sodium chloride + water 3. HCl + NaOH → NaCl + H2O 4. The original solution contained methyl orange. Classic chemistry experiments 121 Titration of sodium hydroxide with hydrochloric acid Introduction In this experiment sodium hydroxide is neutralised with hydrochloric acid to produce the soluble salt sodium chloride. This is then concentrated and crystallised in a crystallising dish. 45 46 47 48 Evaporating dish Titration solution Pipe clay triangle 49 50 Burette Tripod Bunsen burner Conical flask Hydrochloric acid Salt solution Sodium
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