Multiple Choice
Which of the following is a primary reason for keeping lids on chemical containers in a laboratory setting?
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4. BONUS: Lab Techniques and Procedures
Filtration and Evaporation
Multiple Choice
In general, which solvent should be used to wash the solid material collected from a filtration?
A
Any solvent that dissolves the impurities and the solid equally well
B
A large amount of hot solvent in which the solid is highly soluble
C
A concentrated acid solution regardless of solubility
D
A small amount of cold solvent in which the solid is insoluble
Verified step by step guidance1
Understand the purpose of washing a solid after filtration: it is to remove impurities without dissolving the desired solid product.
Recognize that using a solvent in which the solid is highly soluble (especially hot solvent) can cause loss of product because the solid will dissolve.
Avoid solvents that dissolve both impurities and the solid equally well, as this will not effectively separate impurities from the solid.
Avoid using reactive solvents like concentrated acid solutions unless specifically required, because they may react with the solid or cause unwanted side reactions.
Therefore, the best choice is to use a small amount of cold solvent in which the solid is insoluble, so impurities dissolve and wash away while the solid remains undissolved and can be collected.
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