Neco 2025 Chemistry Question 36
Practice objective / multiple choice question 36 from the 2025 Neco Chemistry examination.
A \(0.800\ \text{g}\) sample containing a mixture of calcium carbonate (\(\text{CaCO}_3\)) and sodium carbonate (\(\text{Na}_2\text{CO}_3\)) is treated with \(0.150\ \text{M}\) HCl, \(40.0\ \text{mL}\) being added. The excess acid is back‑titrated with \(0.100\ \text{M}\) NaOH, requiring \(18.0\ \text{mL}\). After the reaction the solid residue is filtered, heated and the mass of CaO obtained is \(0.100\ \text{g}\). Assuming complete conversion of CaCO\(_3\) to CaO, calculate the mass percent of Na\(_2\)CO\(_3\) in the original sample.
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About This Question
This is Neco 2025 Chemistry Question 36. It is one of the objective questions from the 2025 Neco Chemistry examination.
Difficulty level: Hard .
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