Question

When an ion-selective electrode for X was immersed in 0.0680 M XCl, the measured potential was 0.0220 V. What is the concentration of X when the potential is 0.0370 V? Assume that the electrode follows the Nernst equation, the temperature is at 25

Answer 1

case 1

concentration 0.0680 M

potential 0.0220 V

using nernest equation

E=E�?RTlnQ/nF

z for cl = -1

r =8.314 J.K^-1.mol^-1

on putting all values in the equation

we get

concentration of X in intracellular fluid is

Q out is 0.0680 M

so Q in is 28.881019879498897

or 28.9 moles

reference http://www.physiologyweb.com/calculators/nernst_potential_calculator.html

now moving to next part

now Veq is 0.0370 V

Q in is 28.9 moles

Q out ( concentration of) 0.122

t= + 298.15k

activity coefficient = 1.