All your burette readings (initials and final), as well as the size of your pipette, must be recorded but no account of experimental procedure is required. ...
Question 1 Report
All your burette readings (initials and final), as well as the size of your pipette, must be recorded but no account of experimental procedure is required. All calculations must be done in your answer booklet.
State what would be observed if the following reactions are carried out in the laboratory:
(i) methyl orange is dropped into a solution of lime juice:
(ii) hydrogen sulphide gas is bubbled through Iron (III) chloride solution:
(iii) sulphur (IV) oxide gas is bubbled into acidified solution of KMnO\(_4\):
(iv) ethanoic acid is added to a solution of Ka\(_2\)CO\(_3\)
Answer Details
(i) Lime juice is acidic, so methyl orange turns red (pink).
(ii) The yellow/brown iron(III) chloride solution turns pale green (Fe3+ is reduced to Fe2+) and a pale yellow precipitate of sulphur forms, making the solution turbid:
\[2FeCl_3 + H_2S \rightarrow 2FeCl_2 + 2HCl + S\]
(iii) The purple colour of the KMnO4 is decolourized. Sulphur(IV) oxide is a reducing agent and reduces MnO4- (purple) to Mn2+ (colourless).
(iv) There is effervescence and a colourless gas (carbon(IV) oxide) is evolved which turns limewater milky:
\[2CH_3COOH + K_2CO_3 \rightarrow 2CH_3COOK + H_2O + CO_2\]
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