[arcinus]

I was measuring the pH of 5 samples of 10-50mgkg^-1 Na₂S₂O₅ and was hoping to find some linearity in their pH values. However my results came in the form as:
10=3.4
20=4.1
30=3.2
40=4.1
50=4.2

On face value this means to me that the pH of Na₂S₂O₅ is independent of the quantity added. Would this be the correct assumption to make?

[Arkcon]

Since you have a table of data, you can chart it, and also perform  a number of statistical tests on your data.  FWIW, there's no harm in your conclusion, but why not use statistics to see just how correct you are?  Or to what extant you're not able to make your statement?

[arcinus]

the problem I have is that I'm being employed to make what is basically a computer simulation of a boiler system. The output of the pH value that I acquire effects the model substantially as it is involved in multiple processes in the model. Could you think of a reason why this is happening?

[Corribus]

Have you validated your pH measurement procedure?
I.e., if you make the same solution five times, and measure pH, what kind of consistency do you get?

[Borek]

Strange. I am not going to pretend I have ever worked with Na₂S₂O₅, but it looks like a salt of a weak acid (even if wiki says H₂S₂O₅ actually doesn't exist, and says nothing about Ka values), so I would expect the solution to be slightly alkaline, not acidic.