The sulfide content in a pulp plant effluent is determined with a sulfide ion-slective electrode using the method of standard additions for calibration.
A 10.0-mL sample diluted to 25-mL with water gives a potential reading of -214.6mV
A similar 10.0-mL sample plus 1.00 mL of 0.030 M sulfide diluted to 25.0-mL give a reading of -224.0 mV
Calculate the concentration of sulfide in the sample?