Determine whether each cation is acidic or pH neutral. For those cations that are acidic, write an equation that shows how the cation acts as an acid.
A) Sr+2
B) Mn+3
C) C5H5NH+
D) Li+
To determine whether each cation is acidic or pH neutral, we need to consider the nature of each cation and the reaction it may undergo with water.
A) Sr+2 (Strontium ion): This cation does not have any acidic properties since it is derived from an alkaline earth metal. Therefore, it is pH neutral.
B) Mn+3 (Manganese ion): Manganese can exhibit variable oxidation states. In this case, since it has a +3 charge, it can act as an acid. The equation showing how Mn+3 acts as an acid when dissolved in water is as follows:
Mn+3 + H2O → MnO(OH)2 + H+
C) C5H5NH+ (Pyridinium ion): This is a conjugate acid of pyridine, which is a weak base. Therefore, we can consider C5H5NH+ as an acidic cation. The equation showing how C5H5NH+ acts as an acid when dissolved in water is as follows:
C5H5NH+ + H2O → C5H5N + H3O+
D) Li+ (Lithium ion): Lithium ion is derived from a strong base (LiOH), and it does not have any acidic properties. Therefore, it is pH neutral.