Qn: Why can’t we use hydrochloric acid or nitric acid for manganate (VII) redox titrations?
Ans: For HCl, the chloride ion will be oxidised to chlorine gas by manganate (VII) ion.
HNO3 is also an oxidising agent and hence would compete with permanganate.
Lastly, permanganate cannot oxidize sulfate ion and sulfuric acid is not an oxidizing agent.
Therefore, sulfuric acid is the mineral acid of choice for manganate (VII) titrations.
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