Systematic Analysis of Cations

Introduction

The systematic analysis of cations presents inside the element comes to aid many professionals from the field of chemistry to understand the properties of these elements. The experiment shows the quality of cations and their quantity that is observed to lie inside a chemical compound.

Aim of the experiment

The aim of the experiment is to understand the total amount of cations that lies in a mixture of salt. These inorganic salts consist of required amount of cations that have various properties.

Theory of the experiment

The theory of this experiment is to take an approach in order to find the qualitative aspects of the salt. The cationic presence makes a proper set of elements that differ from one another on a single basis. The point of difference lies in the way these elements are going to react with all various sets of “testing reagents”. There are three stages that are able to complete the particular experiment. The first stage looks after the solubility properties of the cations that are classified into a group of 5.

The second stage looks after a group of “precipitated cations” that are divided by a process of selective dissociations. The third stage of this experiment is to find out the number of cations that are done through the process of identification.

Procedure of the experiment

There is a distinct procedure to conduct the experiment that looks after the total number of cations that are seen to lie inside the inorganic salt. For the present experiment, a cavity made of charcoal is used to carry out the whole process. This is the reason why it is usually known as the charcoal cavity test which requires a few steps in total to finalise its completion. The objective of this test is to look after the conversion of metals found in their carbonate form.

Figure 1 − Steps of qualitative analysis of cations

Steps of qualitative analysis of cations, Creative Commons Zero, Public Domain Dedication, via Wikimedia

The entire process of conversion occurs in the cavity carved out of charcoal. In this cavity, the metal carbonates start to undergo a process of decomposition when they are heavily heated. This method of decomposing the metals bearing the structure of carbonates changes itself into metallic oxides. Lastly, the cation that is present inside the cavity can be found in the form of a residue. There is a second way of identifying the presence of cations. In this method, the person is going to see the total amount of cations by looking at the colour of this bead.

Figure 2 − Charcoal cavity test

Charcoal cavity test, Creative Commons Zero, Public Domain Dedication, via Wikimedia

The process of conducting a charcoal cavity test is done by making a small hole inside a block of charcoal. The next step is to take a small amount of sodium carbonate and mix it with a drop of water. Once the paste of sodium carbonate is put inside the cavity it must be heated for some time. The person conducting the experiment must keep the flame under control by using a blowpipe. Once these three steps are done the experiment will show a change in the colour of all the beads present in the cavity.

Observation and results

• Lead $\mathrm{(Pb^{2+})}$ - The element is seen to shine on the bead made of metallic components. The colour is usually yellow and it is able to leave a mark on the paper.

• Silver $\mathrm{(Ag^{3+})}$ - The metallic bead that is supposed to shine inside the cavity is not able to leave a proper mark on the paper.

• Bismuth $\mathrm{(Bi^{3+})}$ - The observation that has been recorded with bismuth is a bead that is brittle in texture. This is the reason why they are made of yellow and brown incrustation.

• Copper $\mathrm{(Cu^{2+})}$ - The observation shows a residue of red colour is left behind after the end of this test. The residue is left behind without any kind of incrustation.

Precautions of the experiment

• The person must put on a pair of gloves with durable clothes.

• The vapour must be inhaled gently to avoid any accidents.

• Prohibit the habit of mixing chemicals without proper supervision.

• The laboratory must be kept neat and clean to avoid cluttering and accidents.

• The phases where heat is applied must be done with proper care.

• Use chemical bottles that have a label.

• Avoid the wastage of chemicals in order to protect the environment.

• Sodium in its metallic form must not be thrown into the sink or trash can.

Conclusion

The tutorial tells the learners about the ways a total number of cations can be found. This can be understood by conducting a test on a charcoal board. The procedure of this experiment shows the way it is done. The images are stated to help the learners visualize the concept of this tutorial.

FAQs

1. How does the charcoal cavity test helps to understand the total number of cations that are present inside the elements?

The total number of cations that are present inside an element can be understood by looking at the colour of these beads change. This transformation of colour is going to occur after the end of this specific test. The other way to learn about this total count is to understand the total amount of leftovers present inside the cavity.

2. What is the colour of zinc carbonate after it changes by going through the process of incustration?

The colour of zinc carbonate is going to change only when the element is hot. Hence the colour of the metal in its carbonate form is yellow.

3. What is formed in the borax bead test to determine the total number of cations?

The borax bead test helps in the identification of cations by reacting with different types of metals. These metals must be present in their oxide form in order to produce metabolites.