CAIE A-Level Chemistry 28.2.1 Ligand Reactions and Complex Formation

Practise equations and observations for Cu2+ and Co2+ complexes with water, ammonia, hydroxide and chloride.

Exam points

write hydroxide deprotonation/precipitation from hexaaqua ions with balanced water products
with excess ammonia, distinguish initial hydroxide precipitate from later ligand-exchange complex
state the formula, colour and reaction type for cobalt water, ammonia or chloride complexes

[Maximum number: 1]

Titanium is a transition element in Period 4. It is commonly found as $\mathrm{TiO}_{2}$ in minerals.

Some reactions of $\mathrm{TiO}_{2}$ are shown in Fig. 3.1.

The anion, acac $^{-}$ , is a bidentate ligand.

Fig. 3.1

Write an equation for the formation of $\mathrm{TiF}_{6}{ }^{2-}$ from $\mathrm{TiO}_{2}$ .

$\begin{aligned} \mathrm{TiO}_{2}+6 \mathrm{HF} \rightarrow \mathrm{TiF}_{6}{ }^{2-}+2 \mathrm{H}_{2} \mathrm{O}+2 \mathrm{H}^{+} \mathrm{OR} \mathrm{TiO}_{2}+6 \mathrm{HF} \rightarrow \mathrm{TiF}_{6}{ }^{2-}+2 \mathrm{H}_{3} \mathrm{O}^{+} \end{aligned}$

All question bank results loaded

28.2.1—Ligand reactions forming complexes question 1