SATHEE: Redox Reactions And Electrochemistry Ques 631

Redox Reactions And Electrochemistry Ques 631

Question: At 298 K, the standard reduction potentials are 1.51 V for $M n O_{4}^{-} | M n^{2 +}, 1.36 V, for C l_{2} | C l^{-}, 1.07$ $V, f o r, B r_{2} / B r^{-}$ , and 0.54 V for $I_{2} / I^{-} . A t p H = 3,$ permanganate is expected to oxidize: $(\frac{R T}{F} = 0.059 V)$

Options:

A) $C l^{-}, B r^{-}$ and $I^{-}$

B) $B r^{-}$ and $I^{-}$

C) $C l^{-}$ and $B r^{-}$

D) $I^{-}$ only

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Answer:

Correct Answer: B

Solution:

[b] $M n O_{4}^{-} + 8 H^{+} + 5 e^{-} \overset{}{\to} M n^{2 +} + 4 H_{2} O$ $E = 1.51 - \frac{0.059}{5} \log \frac{[M n^{2 +}]}{[M n O_{4}^{-}] {[H^{+}]}^{8}}$

Taking $M n^{2 +}$ and $M n O_{4}^{-}$ in standard state i.e. 1 M, $E = 1.51 - \frac{0.059}{5} \times 8 \log \frac{1}{[H^{+}]}$ $E = 1.51 - \frac{0.059}{5} \times 8 \times 3 = 1.2268 V$

Hence at this pH, $M n O_{4}^{-}$ will oxidise only $B r^{-}$ and $I^{-}$ as SRP of $C l_{2} / C l^{-}$ is 1.36 V which is greater than that for $M n O_{4}^{-} / M n^{2 +}$

Redox Reactions And Electrochemistry Ques 631

Question: At 298 K, the standard reduction potentials are 1.51 V for $M n O_{4}^{-} | M n^{2 +}, 1.36 V, for C l_{2} | C l^{-}, 1.07$ $V, f o r, B r_{2} / B r^{-}$ , and 0.54 V for $I_{2} / I^{-} . A t p H = 3,$ permanganate is expected to oxidize: $(\frac{R T}{F} = 0.059 V)$

Options:

Answer:

Solution:

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Redox Reactions And Electrochemistry Ques 631

Question: At 298 K, the standard reduction potentials are 1.51 V for MnO4−|Mn2+,1.36V,for Cl2|Cl−,1.07 V,for,Br2/Br− , and 0.54 V for I2/I−.AtpH=3, permanganate is expected to oxidize: (RTF=0.059V)

Options:

Answer:

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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Question: At 298 K, the standard reduction potentials are 1.51 V for $M n O_{4}^{-} | M n^{2 +}, 1.36 V, for C l_{2} | C l^{-}, 1.07$ $V, f o r, B r_{2} / B r^{-}$ , and 0.54 V for $I_{2} / I^{-} . A t p H = 3,$ permanganate is expected to oxidize: $(\frac{R T}{F} = 0.059 V)$