Does CO2 dissolution in different salt concentrations affects the amount of carbonic acid formed?
100 mL of water and added 5 g of $\ce{CO2}$ and measured the time it took to dissolve completely


This statement doesn't make sense.  Firstly, if you know it dissolved completely, why try to determine how much dissolved?  Secondly, the only way that much CO2 would dissolve is if you did the experiment at high pressure.  

If you want literature data to compare your experiment to, see Fig. 6c or equation 6 of Behaviour of the CO2-H2O system