BioMedical Admissions Test (BMAT) Practice Test

When iron (II) ions react with sodium hydroxide, they form iron (II) hydroxide, which is expressed by the chemical equation: \[ \text{Fe}^{2+} + 2 \text{OH}^- \rightarrow \text{Fe(OH)}_2 \] The resulting compound, iron (II) hydroxide, is known to form a precipitate that exhibits a characteristic light green color. This green color is primarily due to the specific electron transitions within the iron ions and how the precipitate interacts with light. The formation of this light green precipitate is a key observation in qualitative analysis for identifying the presence of iron (II) ions in a solution. The nature of the iron (II) hydroxide precipitate differentiates it from other metal hydroxides that might produce different colors upon precipitation. Understanding these color responses is essential for accurate identification in laboratory settings.