Question

Why is a calibration plot more accurate for determining an unknown than simply comparing the unknown to a single known value?

Answer 1

There are some advantages of calibration plot to determine the concentration of unknown which makes it better than simply comparison of unknown to single known value.

First advantage is that the calibration plot allows to determine the uncertainty. The concentrations is plotted with signal output and it is linearly fit. With that linear fit, the uncertainty can be calculated and thus error can be found out.

The plot gives the empirical relationship of the ion with the signal. So, relationship can be known from the plot. The relationship can be compared with theoretical relationship. There are many factors which can affect the relationship are temperature, pressure etc.

This can not be obtained if we are taking a single known value.