Chemistry experiment questions...?

i think that the free ions in the solution made the bulb more dimmer.. As the reaction H2SO4+ Ba(OH)2 --> BaSO4 + H2O (all numbers are subscripts) goes to completion, the SO4(2-) and Ba(2+) ions get converted to the salt BaSO4 and then after the equivalence point when more Ba(OH)2 is added, more Ba2+ will be present thus increasing the ion concentration of the solution making the light bulb brighter again