Rather large amount of inorganic substances have own high-quality reactions thanks to which it is possible to distinguish them among other connections. Orthophosphoric acid belongs to the class of inorganic, there is the way of its faultless definition among others.
It is required to you
- - test tubes;
- - orthophosphoric acid;
- - silver nitrate;
- - indicators (litmus, methyl orange, phenolphthalein).
Instruction
1. Any inorganic acid represents the difficult connection consisting of atoms of hydrogen and the acid rest. If to consider acid in terms of the theory of electrolytic dissociation (TED), then definition will become a little specified. Acid is the complex substance consisting of positively charged ions (cations) of hydrogen and negatively charged (anions) of the acid remains.
2. For definition of acid it is necessary to carry out two high-quality reactions. The first – on existence of ions of hydrogen. For this purpose it is enough to use indicators which can be paper or in the form of solutions. Such indicators as litmus, methyl orange and phenolphthalein are traditional.
3. Take three test tubes and pour in them 2 ml of orthophosphoric acid. Place a strip of indicator paper in everyone (or flow several drops of solution). In a test tube with litmus solution will become red. In capacity with methyl orange – rose-red. Where there is acid, phenolphthalein will not change the color. All this demonstrates presence at acid test tubes. In the same way it is possible to define also any other substance of this class.
4. To carry out high-quality reaction to phosphate ion, it is necessary to use the reagent giving characteristic change. The reagent confirming existence ortho-phosphate ion is the silver ion. For carrying out experience take a test tube, pour in it 2 ml of orthophosphoric acid then add 1 ml of nitrate of silver which represents soluble salt. Chemical reaction will be resulted by loss of a deposit of yellow color – silver ortho-phosphate. This reaction is qualitative.