When an ionselective electrode for X was immersed in 00490 M

When an ion-selective electrode for X was immersed in 0.0490 M XCl, the measured potential was 0.0410 V. What is the concentration of X when the potential is 0.0560 V? Assume that the electrode follows the Nernst equation, the temperature is at 25

Solution

E = Eo + 0.059/1 log[X+],

0.041 = E0 + 0.059 log(0.049) , Eo = 0.118

0.056 = 0.118 + 0.059 log[X+],

[X+] = 0.0889 M