Question detail
Why is the insoluble reactant added in excess when preparing a soluble salt in a laboratory experiment?
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
Question
Type
exam_style
Style
Topic
Reactions of acids
Question
Why is the insoluble reactant added in excess when preparing a soluble salt in a laboratory experiment?
Answer
Adding the insoluble reactant in excess ensures that all of the acid is consumed, so that the resulting solution contains only the soluble salt and water. If the insoluble reactant were not in excess, some acid would remain unreacted, giving a solution that is still acidic and would not yield a pure salt.
Explanation
The answer explains the rationale behind using an excess of the insoluble solid, showing understanding of stoichiometry and the need to remove all acid to obtain a pure salt. It tests comprehension of the practical reasoning behind the experimental design.
Common mistake
Common Mistake in Salt Preparation
Students often forget to add the insoluble solid in excess when preparing a soluble salt, leading to incomplete reaction and impurities in the final product.
Always add the insoluble solid in excess to ensure that all the acid reacts and to filter out any unreacted solid, resulting in a pure dry sample of the soluble salt.
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