Chemistry Forum

Hello!
I have a question about the alkalinity of three water samples. I did a titration experiment where I firstly titrated seawater , secondly river water and lastly tap water with HCl. I used a color indicator as well in order to see the equilibrium point. Anyways this is what I got :

Alkalinity for 50 ml river water = 244 mg/liter
Alkalinity for 50 ml seawater = 128 mg/liter
Alkalinity for 50 ml tap water = 85,4 mg/liter

Now my question is why is there a difference between those water samples? And why does river water haver the highest alkalinity? Shouldn't it be seawater which has it ?:(

Thanks in advance
Best regards

I think it depends of the geographic location were the sample were taken. Some areas are more alcalne or acidic as others.

Yes. That's correct. I digged myself deeper in this question and find some useful information about that. It says that rivers flow near mountains and through forests and therefore the chance is bigger that alkaline metals that is normally stored underneath the ground can be transferred to river water easily. Which isn't the case for seawater. Anyway thanks for your answer.