2 replies to this topic

How to measure pH for a concentrated chemical mixture when the pH is not within the limit of the digital pH sensor and pH paper?

[P.K.Rao]

pH of a concentrated chemical mixture is generally determined on 1 % solution or extract of the mixture in 7.0 pH water. For this what you do is, take 1 gm of the sample, add 100 ml of 7.0 pH water to it, shake vigorosly for 5 minutes, fliter to remove undissolved matter and determine pH of the filtrate by any method, indicator or pH meter.

[Mr. pH]

pH of a concentrated chemical mixture is generally determined on 1 % solution or extract of the mixture in 7.0 pH water. For this what you do is, take 1 gm of the sample, add 100 ml of 7.0 pH water to it, shake vigorosly for 5 minutes, fliter to remove undissolved matter and determine pH of the filtrate by any method, indicator or pH meter.

While this procedure may be usefull when you need to compare acidity or alkalinity of two different samples, it is of no use when you are interested in the real pH of the solution. But there is no generally accepted method of measuring pH in such cases. Too much depends on the solution composition.