Question

Calibration data for a bromide ion-selective electrode (ISE) was collected and recorded below. The potential of the ISE was measured against a saturated calomel electrode (SCE). All solutions were buffered at a pH of 7.56. A linear calibration curve can be constructed from this data as a plot of potential vs. log[Br-]. Determine the slope and y-intercept of such a plot of the calibration data given.

Find the slope and the y-intercept.

Two unknown solutions were tested for [Br–] using the same bromide ISE. The potential reading for unknown 1 was 13.4 mV and the potential reading for unknown 2 was 181.9 mV. Using the calibration curve you constructed above, determine the concentration of Br– in each unknown solution.

I have done this problem multiple times (5 times) and I cannot figure out what I am doing wrong. I got the slope but not the intercept.

Answer 1

I hope you revisited the ethanol problem After your last post I found two errors; one yours and one mine.