Acid is a complex substance which can be both organic, and inorganic. The general is that they incorporate atoms of hydrogen and the acid rest. The last gives specific properties to each acid and also on it the qualitative analysis is carried out. Any soluble acid in water dissociates (breaks up) to particles – positively charged ions of hydrogen which cause sour properties, and on negatively charged ions of the acid rest.
It is required to you
- - support;
- - test tubes;
- - solutions of indicators;
- - silver nitrate;
- - solutions of acids;
- - barium nitrate;
- - copper shavings.
Instruction
1. To define that in solution there is acid, use the indicator (paper or in solution). Add to capacity to the studied solution litmus which in acidic environment becomes red. For reliability flow other indicator – methyl orange which will change coloring to pink or rose-red. The third indicator, namely phenolphthalein in acidic environment does not change, remaining at the same time transparent. These experiments prove availability of acid, but not specificity of each of them.
2. To define specifically what acid is in a bottle, it is necessary to carry out high-quality reaction to the acid rest. Sulfuric acid incorporates sulfate ion on which reagent is the barium ion. Add the substance containing this ion, for example barium nitrate to acid. Instantly the deposit of white color representing barium sulfate will drop out.
3. Chlorohydrogen (hydrochloric) acid, except hydrogen consists from chloride ion on which the silver ion is considered reagent. For the analysis take solution of nitrate of silver and add to the studied acid. As a result of reaction, silver chloride - a deposit of white color will drop out. It is the proof of presence at solution of ions of chlorine.
4. It is possible to determine by the same reagent (silver nitrate) bromovodorodny acid. As a result receive a white-yellow deposit of bromide of silver. To carry out reaction to yodovodorodny acid also use silver nitrate. The difference will be that the deposit of iodide of silver will become saturated yellow. Thus, on ions of halogens it is possible to use the same reagent – silver nitrate.
5. For definition of the nitric acid containing nitrate ion add copper shavings. Depending on concentration various substances can be formed, however release of brown gas (fox tail) is in most cases observed. Such acid as acetic which belongs to organic it is enough to determine by a smell which is familiar to all since childhood.