Final answer:
The provided information is insufficient to calculate the equilibrium constants for the given reactions without the standard electrode potentials or concentrations at equilibrium.
Step-by-step explanation:
To calculate equilibrium constants for the given reactions, you would need additional information such as the concentrations of the ions at equilibrium or the standard electrode potentials for each half-reaction. Unfortunately, the details provided in the question are not sufficient to calculate the equilibrium constants for reactions (a) Mn(s) + Ti2+(aq) ⇌ Mn2+(aq) + Ti(s) and (b) In3+(aq) + U3+(aq) ⇌ In2+(aq) + U4+(aq) directly.
The equilibrium constant (Keq) is related to the standard electrode potentials for the oxidation and reduction half-reactions. If the standard electrode potentials were known, you could use the Nernst equation to calculate the equilibrium constant. Without this information, I'm unable to provide the equilibrium constants for these specific reactions.