Neco 2023 Chemistry Question 48
Practice objective / multiple choice question 48 from the 2023 Neco Chemistry examination.
A 0.250 g sample of an impure solid containing calcium carbonate (CaCO₃) is dissolved in excess 0.150 M HCl (25.0 mL). The excess acid is then back‑titrated with 0.100 M Na₂CO₃ solution using phenolphthalein as indicator. It requires 12.5 mL of the Na₂CO₃ solution to reach the endpoint. Assuming the dissolution reaction \( \text{CaCO}_3 + 2\text{HCl} \rightarrow \text{CaCl}_2 + \text{CO}_2 + \text{H}_2\text{O} \), calculate the percentage purity of CaCO₃ in the sample.
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About This Question
This is Neco 2023 Chemistry Question 48. It is one of the objective questions from the 2023 Neco Chemistry examination.
Difficulty level: Hard .
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