13 – Standardising a Sodium Thiosulfate Solution (LC 2027) (Leaving Cert Chemistry): Quizzes
📚Quizzes
Practise the questions
12 questions from this quiz
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Practise the questions
12 questions from this quiz
What is standardisation in analytical chemistry?
What is standardisation in analytical chemistry?
Finding exact concentration via titration
Why is a white tile placed under the conical flask?
Why is a white tile placed under the conical flask?
To observe colour changes clearly
What solution does the burette contain in this experiment?
What solution does the burette contain in this experiment?
Sodium thiosulfate (unknown concentration)
What colour appears when excess KI is added to acidified ?
What colour appears when excess KI is added to acidified ?
Reddish-brown
At what stage should starch indicator be added?
At what stage should starch indicator be added?
When solution is pale yellow
What colour appears immediately after adding starch indicator?
What colour appears immediately after adding starch indicator?
Blue-black
What indicates the end point has been reached?
What indicates the end point has been reached?
Blue-black colour disappears completely
Why is excess potassium iodide added?
Why is excess potassium iodide added?
Ensures all reduced
Which reagent must be added before potassium iodide?
Which reagent must be added before potassium iodide?
Dilute sulphuric acid
How should thiosulfate be added near the end point?
How should thiosulfate be added near the end point?
Drop by drop
In the second reaction, what does react with to form ?
In the second reaction, what does react with to form ?
ions
Why is starch NOT added at the start of the titration?
Why is starch NOT added at the start of the titration?
Dark colour makes end point unclear
