An obvious example is the calibration of 0. 1mol/L sodium hydroxide. If oxalic acid is used as reference substance, the method of weighing large samples is adopted. If potassium hydrogen phthalate is used, it is called a sample. Its molar mass is relatively large, and it can have a relatively large mass when weighing a small amount of substances, which can meet the requirement of relatively small error.
I didn't understand this until I reviewed it today. . . .