Aqueous Solutions of Many Metal Cations Have a PH Different

Multiple Choice

Aqueous solutions of many metal cations have a pH different from 7. Which one of the following statements about these cations is not correct?

A) Alkali metal cations such as Na^ and K^ have a negligible effect on the pH.
B) Small and highly charged main group metals such as Al^3 produce acidic aqueous solutions.
C) For transition metal cations, the cation with the higher oxidation state produces more acidic solution; for example, Fe^3(aq) is more acidic than Fe^2(aq) .
D) A solution containing Cr^2 is expected to be considerably more acidic than a solution of equal concentration containing Ni^2.
E) The Lewis acidity of a metal cation is a good measure of its ability to activate a water molecule to lose a proton and produce a hydronium ion.