AP EAMCET202119 Aug 2021Evening ShiftChemistryElectrochemistryActual
Which of the following statement is not correct?
Options
- AFe 3 + / Fe 2 + redox couple has less positive electron potential than Mn 3 + / Mn 2 + couple
- BMnO 4 2 - is a strong oxidizing agent but CrO 4 2 - is not
- CThe second and third series of transition elements have almost similar atomic radii
- DThe E 0 value for Mn 3 + / Mn 2 + couple is much more positive than for Cr 3 + / Cr 2 + couple
Correct answer
B. MnO 4 2 - is a strong oxidizing agent but CrO 4 2 - is not
Step-by-step solution
We know that they are oxyanions of chromium in the 6 + oxidation state and are moderately strong oxidizing agents . In an aqueous solution, chromate and dichromate ions can be interconvertible. whereas MnO 4 2 - is not strong oxidising agent because it's highest oxidation state is + 6 . If the oxidation state of an element increases, its electronegativity also increases. And this is why, permanganate is a strong oxidizing agent. For example, Mn ion has an oxidation state of + 7 in permanganate anion which is wh