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CHEMISTRY, M2 EQ-Bank 9 MC

Which of the following statements best describes a primary standard solution?

  1. It is a solution that must be prepared from a substance with a low molar mass to increase accuracy.
  2. It is a solution prepared using a substance with a precisely known and stable concentration, suitable for use in standardising other solutions.
  3. It is a solution prepared from any chemical, as long as the concentration is measured with a volumetric flask.
  4. It is a solution that can vary in concentration over time and requires frequent standardisation.
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\(B\)

Show Worked Solution

→ Primary standards are used to prepare primary solutions with known and accurate concentrations.

→ A primary standard is a substance that is pure, stable, has a high molar mass (to minimize weighing errors), and is not affected by the atmosphere (such as moisture absorption or \(\ce{CO2}\) interaction).

\(\Rightarrow B\)