Chemistry 5070 · O Level · Ion and ionic bonds

Ion and ionic bonds — practice question

Calcium bromide, $\text{CaBr}_2$, is an ionic solid made up of a lattice containing calcium ions and bromide ions.
(a)[1]

Explain why calcium bromide melts at a relatively high temperature.

(b)[2]

Describe how calcium atoms and bromine molecules react to produce calcium ions and bromide ions, using electron transfer ideas.

(c)[2]

Predict the products formed at each electrode during electrolysis of dilute aqueous calcium bromide.

(d(i))[1]

Ozone is an oxidising agent. Describe the colour change observed when ozone gas is bubbled through aqueous potassium iodide.

(d(ii))[1]

Zinc is a reducing agent. Describe the colour change that occurs when excess zinc is added to acidified potassium manganate(VII).

(e)[2]

The ionic equation for the reaction between aqueous calcium bromide and aqueous chlorine is shown: $2\text{Br}^-(\text{aq}) + \text{Cl}_2(\text{aq}) \rightarrow \text{Br}_2(\text{aq}) + 2\text{Cl}^-(\text{aq})$. Explain, in terms of electrons, why this reaction includes both oxidation and reduction.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Strong electrostatic attraction between oppositely charged ions

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