Qualative Analysis - Lab Report Example

At the end of the practical it was possible to establish the cations present in our unknown sample #19. Qualitative analysis is a method in analytical chemistry which involves the identifying of unknowns in a given solution. It is important in chemistry especially when one is dealing with unknown mixtures to be able to establish the solution properties and the methods of separation if you need to separate. In the general Laboratory set up, qualitative analysis is aimed at getting a deeper understanding of the cations and also learns how to handle them and detect them effectively when in any solution.

The main hypothetical question in qualitative analysis is whether a certain cation is present in a given solution. To prove that hypothesis null, then a series of chemical reactions are conducted and the color changes are mainly used to establish their presence. It should be noted that many cations will have similar color changes and so a series of subsequent reactions are used in the detection of a certain cation (Page & Foster 11). In this lab we divided the cations to be characterized into two sub groups, this was done by selective precipitation.

The precipitate was then separated physically be centrifuging as it settles out and the supernatant liquid decanted. This was the first step where the large group was separated into smaller groups so that a definitive test can be performed to verify the presence or absence of a specific cation. The cations were classified into two groups according to their ability to dissolve. Group A had ( Bi+3, Fe+3 and Mn+2) while group B had (Al+3, Cr+3 and Sn+4) which were to be used in the two labs. The ions were in a combined unknown solution and they were to be analyzed to establish the cations present.

To be sure where any of the cations was present in the solution it was important to run a number of procedures that are described below. In test 1, Mn+2 ions were confirmed present. In the addition of NaBiO3 the color of