State the colour change observed in this precipitation reaction after adding $\text{NaOH(aq)}$ to an aqueous solution of $[\text{Co(H}_2\text{O})_6]^{2+}$.
Complete the ionic equation for the precipitation reaction shown here: $[\text{Co(H}_2\text{O})_6]^{2+} + \ldots \rightarrow \ldots + \ldots$
This precipitation reaction can also be described as a different kind of reaction. Name this type of reaction.
L is an uncharged tridentate ligand. Each L donates three lone pairs to a metal atom or ion. Cobalt forms an octahedral complex ion, E, with L. Complex ion E carries a $2+$ charge. Give the formula of E.
Identify the oxidation state for cobalt in E.
The d-orbitals of the cobalt atom or ion in E are split in energy. State how many d-orbitals lie at a higher energy level and how many lie at a lower energy level.
Define non-degenerate d-orbitals.
Write an equation for the reaction between $\text{Fe}^{2+}$ ions and $\text{MnO}_4^{-}$ ions in acid solution.
Calculate the amount in moles of $\text{Fe}^{2+}$ ions present in $25.0\,\text{cm}^3$ of solution $F$.
Calculate the $M_r$ of $\text{FeCr}_n\text{O}_4$, then use your result to deduce the value of $n$.