Chemistry 9701 · AS & A Level · Nitrogen and sulfur

Nitrogen and sulfur — practice question

Bismuth belongs to Group 15 of the Periodic Table.
(a)[1]

Bismuth shows metallic bonding. Draw a labelled diagram that illustrates the metallic bonding in bismuth.

(b(i))[1]

Bismuth reacts with water to produce bismuth oxide, $\text{Bi}_2\text{O}_3$. A colourless gas that burns with a squeaky pop is also produced. Write an equation for the reduction of water by bismuth.

(b(ii))[2]

$\text{Bi}_2\text{O}_3$ is a yellow insoluble solid with a melting point of $1090\,\text{K}$. The molten substance conducts electricity. Deduce the structure and bonding in $\text{Bi}_2\text{O}_3$. Explain your answer.

(c(i))[1]

$\text{Bi}_2\text{O}_3$ can be used to make $\text{NaBiO}_3$, as shown in equation 1. Equation 1: $\text{Na}_2\text{O} + \text{Bi}_2\text{O}_3 + \text{O}_2 \rightarrow 2\text{NaBiO}_3$. Deduce the oxidation number of Bi in $\text{Bi}_2\text{O}_3$ and in $\text{NaBiO}_3$.

(c(ii))[1]

Identify the reducing agent present in equation 1.

(d(i))[1]

$\text{NaBiO}_3$ acts as an oxidising agent with properties similar to $KMnO_4$. Fig. 1.1 gives an example of $\text{NaBiO}_3$ being used as an oxidising agent. Explain the term oxidising agent.

(d(ii))[1]

Compound X is formed when methylbut-2-ene reacts with $\text{KMnO}_4$. State the key conditions for this reaction.

(d(iii))[4]

Complete Table 1.1 to show the observations when compounds Y and Z react separately with the reagents named.

(d(iv))[1]

Write an equation for the reaction of Z with $\text{NaBH}_4$. Use $[H]$ to show one hydrogen atom from the reducing agent.

(e)[3]

$\text{NaBiO}_3$ can be used to find the concentration of $\text{Mn}^{2+}(\text{aq})$. The ionic equation for the reaction is shown in equation 2. Equation 2: $2\text{Mn}^{2+} + 5\text{BiO}_3^- + 14\text{H}^+ \rightarrow 2\text{MnO}_4^- + 5\text{Bi}^{3+} + 7\text{H}_2\text{O}$. A student carries out the following steps in an experiment: - Place $100.0\,\text{cm}^3$ of a saturated solution of $\text{Mn}^{2+}(\text{aq})$ into a volumetric flask. - Add distilled water to the flask until the total volume is $1.00\,\text{dm}^3$, giving a diluted solution. - Titrate a $25.00\,\text{cm}^3$ portion of the diluted solution with $0.100\,\text{mol dm}^{-3}$ $\text{NaBiO}_3(\text{aq})$. The $25.00\,\text{cm}^3$ portion of the diluted $\text{Mn}^{2+}(\text{aq})$ solution reacts completely with exactly $21.50\,\text{cm}^3$ of $0.100\,\text{mol dm}^{-3}$ $\text{NaBiO}_3(\text{aq})$. Calculate the concentration, in $\text{mol dm}^{-3}$, of $\text{Mn}^{2+}(\text{aq})$ in the saturated solution. Show your working.

Worked solution & mark scheme

This 16-mark question has a full step-by-step worked solution and mark scheme. One marking point: The labelled diagram shows a regular pattern of positive ions

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