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19/01/12 Acids and Bases - Titration

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Revision exercise Acid An acid has a sour taste. Lemon juice is an example of an acid. An acid has a pH value between 0 and 7 Base Indicator Litmus pH

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Stage 1 Use the 10cm 3 pipette and pipette filler to measure out 20cm 3 of sodium hydroxide (NaOH) and put it in the conical flask Make sure to match the bottom of the meniscus with the scale on the pipette.

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Stage 2 - Titration Titrations are used to very accurately add a certain amount of an acid to a base. Fill the burette accurately with 50cm 3 of Hydrochloric acid (HCl) Remember to line up bottom of meniscus 12 3

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Stage 3 - Evaporation Place the resultant solution from the final titration into an evaporating dish Put the dish on a gauze on a tripod Heat the dish with a Bunsen burner until all the liquid is gone

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To titrate hydrochloric acid (HCl) against sodium hydroxide (NaOH) and prepare a sample of salt NaCl For our experiment we are using 1M HCl with a pH value of 0 And 1M NaOH with a pH value of 14 We add the HCl to the NaOH What do you think will happen to the pH value of the resulting solution?

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To titrate hydrochloric acid (HCl) against sodium hydroxide (NaOH) and prepare a sample of salt NaCl Stage 1 Stage 2 Stage 3 12 3

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Discussion of results Titration No. Volume of HCl added (cm 3 ) We have just performed a neutralisation reaction. The addition of the HCl lowered the pH of the solution to 7 Neutralisation ACID + BASE = SALT + WATER HCl + NaOH = NaCl + H 2 O Can you think where this type of reaction might be useful in everyday life?