Calibration of a glass electrode gave a reading of 148.7 mV with 0.05 m potassium dihydrogen citrate buffer standard (pH = 3.766) and a reading of -167.4 mV with 0.01 m borax buffer standard (pH = 9.139), both measured at 30°C.
(a) What is the observed slope (mV/pH unit) of the calibration curve?
(b) What is the theoretical slope at 30°C?
(c) What is ?, the electromotive efficiency to three significant figures??
(d) What is the pH of an unknown that gives a reading of 41.7 mV with this electrode at 30°C?