Redox Titration 2: Iodine and Sodium Thiosulfate (Leaving Cert Chemistry): Quizzes
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Practise the questions
10 questions from this quiz
What does the 'pent' in pentahydrate refer to in ?
What does the 'pent' in pentahydrate refer to in ?
Five water molecules in the structure
What does the prefix 'thio' indicate in thiosulfate ion structure?
What does the prefix 'thio' indicate in thiosulfate ion structure?
Sulfur has replaced oxygen
What is the product when thiosulfate ions are oxidized by iodine?
What is the product when thiosulfate ions are oxidized by iodine?
Tetrathionate ion ()
What is the molar ratio of iodine to thiosulfate in the titration reaction?
What is the molar ratio of iodine to thiosulfate in the titration reaction?
1:2
Why can't sodium thiosulfate be used to prepare standard solutions by direct weighing?
Why can't sodium thiosulfate be used to prepare standard solutions by direct weighing?
The crystals are efflorescent
When should starch indicator be added during the iodine-thiosulfate titration?
When should starch indicator be added during the iodine-thiosulfate titration?
When the solution becomes pale yellow
In the iodine-thiosulfate reaction, which substance acts as the reducing agent?
In the iodine-thiosulfate reaction, which substance acts as the reducing agent?
Thiosulfate ion
What color change indicates the endpoint when starch indicator is used?
What color change indicates the endpoint when starch indicator is used?
Blue-black suddenly disappears
Why is excess potassium iodide added to keep iodine in solution?
Why is excess potassium iodide added to keep iodine in solution?
It forms triiodide ion ()
Why should iodine solutions be kept in dark bottles during storage?
Why should iodine solutions be kept in dark bottles during storage?
To prevent decomposition