Question

Question 4 of 4 > Potential (my -21.9 Calibration data for a bromide ion-selective electrode (ISE) was collected and recorded in the table. 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 (in mV) vs. pBr. Determine the slope and y-intercept of such a plot of the calibration data given. [Br"](M) 0.300 0.0300 0.0000 0.000300 36.2 95.6 154.9 0.0000300 224.8 mVy-intercept = slope = my Two unknown solutions were tested for [Br" using the same bromide ISE. The potential reading for unknown 1 was 17.4 mV, and the potential reading for unknown 2 was 105.9 mV. Using the calibration curve you constructed, determine the concentration of Br in each unknown solution. unknown ! [Br] = M unknown 2 [Br"]=

Answer 1

Br (M) por = log10 [Br] Potential(mv) 0.3 0.523 -21.9 0.03 1.523 36.2 0.003 2.523 95.6 0.0003 3.523 154.9 0.00003 4.523 224.8 plot of potential vs pBr y = 61.21x - 56.513 Potential(mv) pBr

4 @ por is given as p Br = -log[BY-] Br for all situations on g will calculate excel plot. From the plot slope = 61.21 mV and y-intercept = -56.513 mv obtained the From the plot, we equation y = 61.2/x - 56.513 Here, y= potential in mv 1 x= pBr Solution (i): i) y = 17.4 m V ... X = p By = y + 56.513 AV . 61.21 mv (17.4 + 56.513) mV 61.21 mV 1. 207 ..[8] = 67.207) 10 Sinic p Br = -109 (3) = 0.062 M Any

Solutim II y = 105.9 mV y + 56.513 MV long SEPT 61.21 mv (105.9 +56.5137 V 61.21 mx ♡x = 2. 653 Since x= p Br = -log [>-] = 2.653 : [Br J = 162.653) = [B0-] = 0.0022 M Aru