Redox Reactions And Electrochemistry Ques 714
Question: A current of 0.250 A is passed through 400 mL of a 2, 0 M solution of NaCl for 35 minutes. What will be the pH of the solution after the current is turned off-
Options:
A) 12.98
B) 12.13
C) 10.48
D) 9.24
Show Answer
Answer:
Correct Answer: B
Solution:
[b] After electrolysis aqueous NaCl is converted into aqueous NaOH. The quantity of electricity passed $ =\frac{0.250\times 35\times 60}{96500C}A,s=5.44\times {10^{-3}}F $
The number of equivalents of $ O{H^{-}} $ ion formed $ =5.44\times {10^{-3}} $
$ \therefore $ Molarity of $ NaOH=\frac{5.44\times {10^{-3}}}{0.400L}eq. $ $ =1.36\times {10^{-2}} $
$ pOH=-\log (1.36\times {10^{-2}})=2.00-0.13=1.87 $
$ \therefore $ $ pH=12.13 $
