Complete Table 2.1 by giving the formula and colour of each cobalt-containing species found in A, B and C. Also identify the reaction type that forms each of B and C.
Suggest a suitable reagent to form $[\text{CoCl}_4]^{2-}$ from solution A.
Complete Fig. 2.2 to indicate the relative energies of the $3d$ orbitals in an isolated $\text{Co}^{2+}$ ion and in $\text{Co}^{2+}$ within a tetrahedral complex.
Draw a three-dimensional diagram showing the structure of the complex ion $[\text{CoCl}_4]^{2-}$.
H_2O_2 can act as oxidising agent or reducing agent when reacting with species that contain manganese. Table 2.2 gives electrode potentials, $E^{\circ}$, for some electrode reactions. Using only the species listed in Table 2.2, suggest: one reaction in which $\text{H}_2\text{O}_2$ acts as an oxidising agent and one reaction in which $\text{H}_2\text{O}_2$ acts as a reducing agent. Include the value of the standard cell potential, $E^{\circ}_{\text{cell}}$, and an overall equation for each reaction.
Describe the colour change seen at the end-point of this titration. from ................................ to ................................
Calculate the mass, in mg, of iron in one tablet. Assume that every iron atom in the tablets is present as $\text{Fe}^{2+}$. Show your working.