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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: gracie on April 08, 2005, 11:28:28 AM

Title: why use sulphuric acid as solvent for potassium dichromate and K. permanganate?
Post by: gracie on April 08, 2005, 11:28:28 AM

 Just a quick question on why sulphuric acid is used as the solvent when making up potassium dichromate and potassium permanganate?
 In the case of the KMnO4 i know that HCl is unsuitable as the Cl is an oxidising agent but other than the stability of potassium dichromate in H2SO4, im not sure.
            Thanks.

Title: Re:why use sulphuric acid as solvent for potassium dichromate and K. permanganat
Post by: Garneck on April 08, 2005, 11:44:51 AM

Cl- is a reducing (not oxidising) agent for KMnO4. (Or my chemistry english is getting bad)

I'd say it's because of the same reason. K2Cr2O7 is a strong oxidiser.

Oh, and when they reduce, H+ causes them to reduce to lower oxididation states. In H+, permangate MnO₄^- reduces to Mn²⁺, while in OH- only to MnO₄^2-