Redox Reactions And Electrochemistry Ques 723
Question: Which of the following is correct statement-
Options:
A) Conductivity & molar conductivity of solution increase on dilution
B) Voltage of button cell remain unchanged throughout its life time
C) On electrolysis of aqueous $ CuSO_4 $ using platinum electrode its concentration $ [C{u^{2+}}] $ remain constant
D) On electrolysis of aqueous $ NaCl, $ solution becomes acidic
Show Answer
Answer:
Correct Answer: B
Solution:
[b] (1) Conductivity decrease with increase in dilution while molar conductivity increases with increase in dilution.
(2) Voltage of button cell remain constant throughout its life time because the overall reaction does not involve any ion in solution whose concentration can change during its life time.
(3) At cathode: Discharge potential of $ C{u^{2+}}< $ discharge potential of $ {H^{+}} $
$ \therefore $ $ C{u^{+2}}(aq)+2{e^{-}}\xrightarrow[{}]{{}}Cu(s) $ So concentration of $ C{u^{2+}} $ decreases with time.
(4) On electrolysis of aqueous $ NaCl, $ At cathode: $ {H^{+}}(aq)+{e^{-}}\xrightarrow[{}]{{}}\frac{1}{2}H_2(g) $ At anode $ C{l^{-}}(aq)\xrightarrow[{}]{{}}\frac{1}{2}Cl_2(g)+{e^{-}} $ so $ O{H^{-}} $ remain in the solution. So solution become basic.
