I got a high 7 for my Chemistry HL Internal Assessment. The topic was “To investigate the effect of charge density and pH of a ligand on its ability to substitute ligands of a complex ion in ligand substituting reaction, measured by comparing the pH and maximum absorption wavelength”
Investigating the effect of charge density and pH of a ligand on its ability to substitute ligands of a complex ion in ligand substituting reaction, measured by comparing the pH and maximum absorption wavelength absorbed by the complex ion before and after the substitution
As a child, my favorite hobby was to mix color paints to see how a new color would form. I have always been observing the color change, after mixing the paints, without knowing what the theory behind such color changes were. But in my first year of IB Chemistry, I have learnt that, in inorganic Chemistry, most observable color changes occur due to exchange of ligands in complex ions. This was a total shock to me as it meant that all color changes that occurred when I mixed color paints, were chemical reaction called the ligand substitution reaction, which I haven’t ever heard of before, but I was setting up the environment for the reaction to take place every time I mixed paints together. So, I started to learn about the complex ions in more detail.
Complex ions were unique in that they have half-full electrons in d-orbitals that are capable of: forming compounds with various oxidation numbers, forming a variety of ions, acting as catalyst when either elements or compounds, and exhibiting colors. The unique chemical property of complex ion that has rose my interest was the theory behind how complex ions exhibited colors. Color that a complex ion exhibits depended on the nuclear charge of the central metal ion, charge density of the ligands, geometry of the complex, and the number of d-orbital electrons the central metal ion had. Since I knew, from IB Physics, that the color we see is directly related to the maximum wavelength an object can reflect, I wondered how different charge densities of ligand would alter the different maximum wavelength the object can reflect.
So, I have decided to investigate the trend in the color change of inorganic compounds, that occur due to ligand substitution reaction, when the charge density of the ligands is varied. As I was selecting ligands of different charge densities to test, I have noticed that most ligands can be classified as acids or base.
Therefore, I have decided to add to my investigation, the role of the acidity of ligands on its ability to substitute ligands in a ligand substitution reaction, along with the trend in the maximum absorption unit a complex ion can reflect under ligands of different charge densities with different pH.
2. Research Question
Investigation into the effect of the charge density and pH of Lewis base ligands on its ability to substitute ligands in ligand substitution reaction, measured by comparing the change in pH and visible-spectrophotometry absorbance of complex ion before and after ligand substitution reaction…
- Total number of pages: 12 pages
- Topic: To investigate the effect of charge density and pH of a ligand on its ability to substitute ligands of a complex ion in ligand substituting reaction, measured by comparing the pH and maximum absorption wavelength
- Subject: Chemistry
- The file is in PDF format.