Yes they will react in liquid form, this is because:
Since in liquid state, the ions are separate, while in the solid state the ions form aggregates and are tightly bound to each other.
The ions are separate in liquid state, because they are loosely bound because we break the interionic forces ( not completely, though) which prevail in the solid state.
And the reaction that takes place between them is ionic substitution only, so yes they can react.