Which species is the classic strong oxidizing agent in acidic solution?

Which species is the classic strong oxidizing agent in acidic solution?

• A. MnO4-
• B. CN-
• C. HCO3-
• D. Cr2O7^2-

Answer: (A)

In acidic solution, the strength of an oxidizing agent is tied to how readily it gains electrons, which is reflected in its reduction potential under acidic conditions. Permanganate (MnO4−) is reduced to Mn2+ with a very high standard reduction potential (about +1.51 V in acid). That large positive value means MnO4− pulls electrons from many other species very readily, making it a powerful oxidizer in acidic medium. Cyanide (CN−) is actually a reducing agent; it donates electrons and is oxidized itself, not the oxidizer in question. Bicarbonate (HCO3−) is not an oxidizing agent in acidic solution. Dichromate (Cr2O7^2−) in acid is also a strong oxidizer, but its reduction potential is lower than that of permanganate, so MnO4− is the stronger, more classic oxidizing agent under these conditions.

In acidic solution, the strength of an oxidizing agent is tied to how readily it gains electrons, which is reflected in its reduction potential under acidic conditions. Permanganate (MnO4−) is reduced to Mn2+ with a very high standard reduction potential (about +1.51 V in acid). That large positive value means MnO4− pulls electrons from many other species very readily, making it a powerful oxidizer in acidic medium.

Cyanide (CN−) is actually a reducing agent; it donates electrons and is oxidized itself, not the oxidizer in question. Bicarbonate (HCO3−) is not an oxidizing agent in acidic solution. Dichromate (Cr2O7^2−) in acid is also a strong oxidizer, but its reduction potential is lower than that of permanganate, so MnO4− is the stronger, more classic oxidizing agent under these conditions.