Acids, Bases and the pH Scale — O/L Science

How do I practise Acids, Bases and the pH Scale?

1 question with a worked solution · 6 marks

1. 2021 · Paper II · 6 marks
   Question 5 gives the universal-indicator colours and pH values a student obtained for four unnamed solutions. It asks you to sort them into acidic, neutral and alkaline, to write the word equation for the neutralisation between the strongest acid and the alkali, and to name one everyday use of an alkali.
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   (i) Acidic: A (pH 2) and D (pH 4); Neutral: B (pH 7); Alkaline: C (pH 11). (ii) Acid + Alkali → Salt + Water (i.e. hydrochloric acid + sodium hydroxide → sodium chloride + water). (iii) Toothpaste / baking soda for cooking / lime to neutralise acidic soil (any valid example accepted).
   Source: Department of Examinations, Sri Lanka — G.C.E. O/L Science 2021, Paper II, Question 5 · https://doenets.lk/pastpapers

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