The half-cell Cr₂O₇ ^2– + 14H⁺ + 6e^–  ⇌ 2Cr³⁺ + 7H₂O has an  E^θ value of +1.33 V.

a. Suggest how the value of E^θchanges if the other species are kept at 1.00 mol dm^–3 but:

i. [Cr₂O₇^2–] is increased

ii. [H⁺] is decreased

iii. [Cr³⁺] is increased.

b. What effect would each of these concentration changes have on the strength of the acidified Cr₂O₇^2– solution as an oxidising agent?

c. What conditions would you use to make a solution of Cr₂O₇^2– as strong an oxidising agent as possible?

d. Use Le Chatelier’s principle to explain your answer to part c.