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CGP EDU Academic Team
Published on: August 14, 2026
At 298 K, the standard reduction potentials are 1.51 V for MnO 4 – |Mn 2+ , 1.36 V for Cl 2 |Cl – , 1.07 V for Br 2 |Br, and 0.54 V for Ι 2 | Ι – . At pH = 3, permanganate is expected to oxidize : 
Text Solution
Verified by ExpertsThe correct answer is:
B
+ 8H + + 5e – ⎯→ Mn 2+ + 4H 2 O
E = 1.51– 
log 
Taking Mn 2+ and 
in standard state i.e. 1 M,
E = 1.51 – 
× 8 log 
= 1.51 – 
× 8 × 3 = 1.2268 V
Hence at this pH, 
will oxidise only Br – and I – as SRP of Cl 2 /Cl – is 1.36 V which is greater than that for 
/Mn 2+ .
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