Would NaBr behave in the same way as NaCl :[ pH of NaCl solutions will be slightly below 7, but this is caused by "ionic strength effect" (influence of ionic strength on activity of H+ ion) ] ?
Yes, I would expect exactly the same problems here. Note - they will be not time dependent, ie pH will not change in time. If the pH changes it is most likely due to some additional effect, like CO2
What is the effect of the solution's concentration on this phenomena?
Good question. Most often used theory (Debye-Huckel theory
) works OK for solutions of ionic strength up to 0.1, with some extensions they can be used up to ionic strength 0.5 (in the case of Me+
salt ionic strength is identical with its molar concentration). Your solution is far more concentrated. Most likely activity coefficients are much higher than 1 then.
What is the expected relation/trend between the Halide (as F,Cl,Br & I) of Na & the magnitude of this effect?
As a first approximation, ionic strength is what counts, type of halide is of secondary importance. F-
is a weak base, so it will hydrolize.
I would definitely stick to pH measurements in the diluted solution.