[AngieZ1]

I am trying to figure out how to calculate the resulting pH when I add acidic water (pH =2.2) to a water with high alkalinity content (350 ppm of CaCO3)

[Borek]

Not enough information.

[AngieZ1]

I am trying to calculate the resulting pH of a water that has a known alkalinity (say 350 ppm), hardness content (300 ppm) and pH of 7.5 after adding acid water of pH=2.2.

I have assumed that the acidic water neutralizes some of the alkalinity in the water (bicarbonate), but how can I calculate the pH of the resulting water?

Any input on this would be greatly appreciated.

[Borek]

As I told you, it is not possible to solve the problem. Just knowing initial pH of acidified water is not enough.

[AngieZ1]

This acidified water is water that has passed through an strong cation ion exchange resin of the H+ form.  Around 0.4 L of this acidified water is sent to a 1L of the water with high alkalinity content (350 ppm CaCO3 alkalinity, 300 ppm CaCO3 Hardness, ~ 370 TDS and pH = 7.5)

What other information or assumptions would one need to be able to estimate the final pH?
Thanks for your help.

[Borek]

Still not enough. It could be enough if you assume low pH water didn't contain (before being passed through the resin) any anions of the weak acids. Then it is possible to estimate final pH assuming concentration of H⁺ to be that given by pH and calculating how much CO₃^2- was present and able to neutralize H⁺. But if the original solution contained any anions of weak acids, the result obtained this way won't be worth anything.