Final answer:
The precise cell potential of an electrochemical cell upon adding potassium dihydrogen arsenate cannot be determined without specific information about the half-reactions involved. Standard conditions and the presence of overvoltages significantly affect the cell potential, and without further details, we can only refer to the standard potential for electrolysis of water, which is -1.229 V.
Step-by-step explanation:
The expected cell potential for an electrochemical cell with the addition of 8.0 mL of a 1.00 M solution of potassium dihydrogen arsenate cannot be determined directly without additional information about the half-reactions involved with potassium dihydrogen arsenate. However, we know that for water electrolysis in a standard electrochemical cell, where the anode reaction is 2H₂O(l) → 2H₂(g) + O₂(g), the Ecell is -1.229 V. This standard potential indicates a nonspontaneous reaction that requires an external voltage to proceed. The actual cell potential would differ when non-standard conditions apply, such as variations in concentration or pH, and the presence of overvoltages.
Adding potassium dihydrogen arsenate, which can affect the concentration of H+ in the solution, will alter the pH and, consequently, the cell potential. However, without specific half-reaction potentials for the arsenate reaction, and knowing that concentrations are no longer standard, we cannot provide an exact cell potential value. For water to be electrolyzed, typically a voltage about 0.4-0.6 V greater than the calculated standard potential is necessary to account for overvoltage. To predict the direction and driving force of an electrochemical reaction accurately, chemists use the standard cell potential (E°cell), measured under standard conditions with all species in their standard states.
It's important to remember that corrections for non-ideal behavior are significant for precise quantitative work and can affect the cell potential. Also, the measured potential of a cell strongly depends on the concentrations of reacting species and the system's temperature. Since precise quantitative values for potassium dihydrogen arsenate's effect on the cell's potential are not provided, a precise value cannot be calculated.