A 500-mL aqueous solution of NaCl was electrolyzed for 15.0 minutes, producing Cl2 gas at the anode. If the pH of the final solution was 12.15, calculate the average current used. (hint: what products are produced at the cathode?)

A. 3.8 A
B. 2.2 A
C. 0.47 A
D. 1.4 A
E. 0.76 A

NaCl+H2O>> NaOH + Cl2 + H2

does that help?

.76 A

To calculate the average current used during the electrolysis, we need to first determine the amount of charge transferred during the process. The amount of charge transferred can be calculated using Faraday's law of electrolysis.

Faraday's law states that the amount of charge (Q) transferred during electrolysis is directly proportional to the number of moles (n) of the substance being oxidized or reduced and the Faraday constant (F), which is equal to 96,485 C/mol.

Since Cl2 gas is being produced at the anode, it means that Cl- ions are being oxidized to form Cl2 gas, releasing electrons in the process. At the cathode, water (H2O) is typically reduced to produce H2 gas.

First, we need to calculate the number of moles of Cl2 gas produced. Since the volume of the aqueous solution is given as 500 mL, we can assume that the concentration of NaCl is 1 mol/L (since 1 L = 1000 mL). Therefore, the number of moles of NaCl is 0.5 moles.

From the balanced equation for the electrolysis of NaCl, we know that 1 mole of Cl2 gas is produced for every 2 moles of electrons transferred.

So, the number of moles of Cl2 gas produced can be calculated as follows:

moles of Cl2 gas = 0.5 moles of NaCl / 2 = 0.25 moles of Cl2 gas

Now we can calculate the charge transferred (Q) using Faraday's law:

Q = n × F
= 0.25 moles × 96,485 C/mol
= 24,121.25 C

The time taken for the electrolysis is given as 15.0 minutes. To calculate the average current (I), we need to convert this time to seconds:

Time (t) = 15.0 minutes × 60 seconds/minute
= 900 seconds

Now we can calculate the average current (I) using the equation:

I = Q / t
= 24,121.25 C / 900 s
≈ 26.80 A

Therefore, the average current used during the electrolysis is approximately 26.80 A.

However, the question asks for the pH of the final solution, not the average current. To determine the pH, we need to understand the chemistry involved. Since Cl2 gas is produced at the anode, it reacts with water to form hypochlorous acid (HOCl) and hydrochloric acid (HCl). This leads to the formation of H+ ions in the solution, resulting in a decrease in pH.

Since the pH of the final solution is given as 12.15, it indicates that the solution is basic, not acidic. This suggests that there might be a mistake or conflicting information in the question, as the production of Cl2 gas should lead to an acidic solution.

Therefore, the correct answer cannot be determined based on the given information.