I am working with the following equation

V_b= V_a [(C_a/(1+([H^+])⁄K_a ) - [H^+] + K_w/([H^+]))/(C_b/(1+K_w⁄([H^+]K_b )) + [H^+ ] - K_w/([H^+]))]

C_a, C_b, K_a, K_b, K_w and V_a are all constants or have known values. I want to set up a range of values for V_b from which to calculate [H^+ ]. This is not a trivial problem and I need to know how the calculation can be performed.

Maybe using the Solver add-in (perhaps not) or by writing code in VBA. If the latter I would need help in writing the code because I am not a mathematician.

Expected result for C_a = 0.1, C_b = 0.1, K_a = 1.74E-5, K_b = 0.63, K_w = 1.0E-14, V_a = 25, [H^+] = 1.95E-9 is V_b = 25 (or close to)