Question

The pH of 0.5 L of 1.0 M NaCl solution after electrolysis for 965 s using 5.0 A current is:

• A. 1.0
• B. 12.7
• C. 1.30
• D. 13.0

Hint:

Electrolysis of NaCl solution produces NaOH, increasing pH significantly.

Answer 1

The Correct Option is D

Step 1: Understanding the Electrolysis of NaCl Solution
Electrolysis of NaCl solution produces NaOH.
The reaction at the cathode generates OH$^-$ ions, increasing pH.
Step 2: Calculating the Number of Moles of NaOH Formed
Total charge passed: \[ Q = It = 5.0 \times 965 = 4825 { C} \] Moles of NaOH produced: \[ \frac{4825}{96500} = 0.05 { mol} \] Step 3: Calculating pH
Molarity of NaOH: \[ \frac{0.05}{0.5} = 0.1 M \] pOH: \[ {pOH} = -\log(0.1) = 1 \] pH: \[ {pH} = 14 - 1 = 13 \] Thus, the correct answer is (D).