What is the difference between Standard solution and Primary standard solution & secondary standard solution?
The term “primary standard” is used for compounds that are extremely pure and stable with no water of hydration. Read through the link to see what the term means in more detail. NaOH can be standardized using a primary standard but is chemically reactive and will pick up water and CO2 from the atmosphere over time. Its reactivity with water is rapid and occurs while weighing out the pure NaOH, making its assay uncertain. The primary standard used for NaOH is potassium hydrogen phthalate, KHP. This makes NaOH a secondary standard at best. Your tutor is mistaken in this case. Be gentle. Hope this helps.
