Alternative measure of acidity. What is measured?
So we stayed on the fact that the measurement medium acidity using indicator paper may be inaccurate. How can I avoid this?
The most effective way - to spend alternate dimension. For example, use a digital sensor of acidity.
Try in the most general terms to understand how such a sensor is arranged. To do this, we need to deal with the fact, and what is acidity? What do we measure? To understand this, let's try to understand what substances are acids. The simplest definition assumes that the acid is a complex substance containing hydrogen atoms which can be substituted by metal atoms, and the acid residue (such a determination gave the acid in the 19th century, Justus Liebig).
In 1887, Svante Arrhenius and Wilhelm Ostavld, and later the Russian chemist Ivan Kablukov showed that some substances, including acid when dissolved in water fall (in the scientific, dissociate) to charged particles - ions. Moreover, in the case of acids only a positively charged ion (cation) ions are H + (ie, protons). So far, aside the reasons for this process. Let us consider the most important thing. Quantity of hydrogen ions in the solution determines the acid strength. That is the value we measure when we determine pH