Experiment 15: TO DETECT ACID RADICAL PRESENT IN GIVEN INORGANIC SALT (S2)
OBJECTIVE
TO DETECT THE ACID RADICAL PRESENT IN GIVEN INORGANIC SALT (S2) BY WET WAYS
APPARATUS REQUIRED
- Test tube
- Test tube holder
- Test tube stand
CHEMICALS REQUIRED
- AgNO3
- BaCl2
- HNO3
- HCl
THEORY
Qualitative inorganic analysis is concerned with detecting and identifying radicals present in inorganic salt or a mixture of salts. Inorganic salts are the outcome of the neutralization of acids with base. Each inorganic salt consists of two parts. The part contributed by acid is called acid radical or anion and the part contributed by base is called basic radical or cation. For example, in sodium chloride, which can be obtained by the neutralization of base NaOH with acid HCl, Na+ is the basic radical and Cl- is the acid radical.
PROCEDURE
The original solution was prepared by dissolving the given salt sample in water. The sample was subjected to several tests to detect acid radicals in the salt.
PHYSICAL PROPERTIES
- State: Crystalline solid
- Colour: White
- Odour: Odourless
- Solubility: Soluble in water
OBSERVATION TABLE
| Experiment | Observation | Inference |
| 1. AgNO3 test: 2 ml of original solution was taken in a clean and dry test tube and few drops of barium chloride solution was added to it. | White ppt. was not formed. | Absence of halide ion. |
2. BaCl2 test 2 ml of the original solution was taken in a clean and dry test tube and a few drops of barium chloride solution was added to it. | White ppt. was formed that dissolves in dilute HCl | Presence of CO3– – |
3. Ring test 2 ml of the original solution was taken in a clean and dry test tube and double the volume of conc. H2SO4 was added. The content was cooled and freshly prepared FeSO4 was added through the walls of the test tube and was allowed to stand for sometime | Brown ring was not formed. | Absence of NO3– – |
Reactions involved
\begin{align*}
CO_{3}^{--}+BaCl_{2} &\rightarrow \underset{white\ ppt.}{BaCO_{3}}+2Cl^{-}\\
BaCO_{3}+HCl\rightarrow &BaCl_{2}+H_{2}O+CO_{2}
\end{align*}RESULT
The acid radical present in the given inorganic salt was found to be CO3— (carbonate ion).
CONCLUSION
We can detect the acid radical present in given inorganic salt by wet ways.
PRECAUTION
- Salt solution should be used in small amounts.
- The salt solution should not be too concentrated.
- The test tube should be clean and dry.
