Potential—pH relations of synthetic beta manganese dioxide in NH4Cl Solutions

✍ Scribed by I. Tari; T. Hirai

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 365 KB
• Volume: 26
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(81)85142-0

✦ Synopsis

Ah&act

-The potential of synthetic beta manganese dioxides was measured in NH,CI solutions as a function of pH. Since both the dioxides were stoichiometric and the solutions dim not contain any trace of manganous ions, pH-response of the potential was expected to he -0.059V.pH-r at 25°C. However, potential-pH relations obtained had two lines, one having a slope of -0.090 _ -O.lOOV.pH-I in the pH region below about 7 and the other having a slope of -0050 V.pH -' in the pH region beyond about 7. It was found that former steeper slope could be explained by assuming the presence of dissolved manganous ions from the oxide surface, which contribute to a greater pH-response of the potential.