Cobalt(II) nitrate, $\text{Co(NO}_3)_2$, is a reddish-brown crystalline solid. When it dissolves in water, it forms a solution containing $[\text{Co(H}_2\text{O})_6]^{2+}$ complex ions.
(a(i))[2]
Complete Table 4.1 with the formula of the cobalt-containing species formed in each of the three reactions described.
(a(ii))[1]
Describe the colour change observed in reaction 3.
(b(i))[1]
Write an equation for the thermal decomposition of $\text{Ca(NO}_3)_2$.
(b(ii))[3]
Suggest temperatures at which $\text{Mg(NO}_3)_2$ and $\text{Ba(NO}_3)_2$ begin to decompose. Explain your answer.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Correctly identified cobalt(II) complex species (any two)” …