Chemistry 9701 · AS & A Level · Group 17

Group 17 — practice question

Iodine participates in a wide variety of inorganic and organic reactions.
(a(i))[2]

State and explain the pattern in volatility of the halogens from chlorine to iodine.

(a(ii))[1]

Explain why HI is the least thermally stable of HCl, HBr and HI.

(a(iii))[2]

The table lists the electronegativity values for hydrogen, fluorine and iodine. Explain, in terms of intermolecular forces, why HI has a lower boiling point than HF.

(a(iv))[1]

Iodine reacts with hot concentrated aqueous sodium hydroxide in the same way as chlorine. Write an equation for the reaction of iodine and hot aqueous sodium hydroxide.

(b(i))[1]

The simplest iodoalkane is $\text{CH}_3\text{I}$. $\text{CH}_3\text{I}$ can be prepared from methanol, $\text{CH}_3\text{OH}$. Identify a reagent that can convert $\text{CH}_3\text{OH}$ to $\text{CH}_3\text{I}$.

(b(ii))[1]

$1,2$-diiodoethane, $\text{CH}_2\text{ICH}_2\text{I}$, can be made by bubbling ethene into liquid iodine. Fully name the type of mechanism shown in this reaction.

(c(i))[1]

$J$ reacts with NaOH, forming different products depending on the conditions used. Name $J$.

(c(ii))[1]

$J$ reacts with $\text{NaOH(aq)}$ to form $K$. Fully name the mechanism of the reaction of $J$ with $\text{NaOH(aq)}$ to form $K$.

(c(iii))[1]

$\text{J}$ reacts with $\text{NaOH}$ dissolved in ethanol to give a mixture of two alkenes, $\text{L}$ and $\text{M}$. Alkene $\text{L}$ is shown. In the box provided, draw the structure of $\text{M}$.

(c(iv))[1]

Explain why $\text{L}$ does not show geometrical (cis-trans) isomerism.

(c(v))[1]

$\text{L}$ reacts with hot concentrated acidified $\text{KMnO}_4\text{(aq)}$ to form propanone and one other organic product. Identify the other organic product.

(c(vi))[2]

When propanone reacts with excess alkaline aqueous iodine, complete and balance the equation for this reaction. $\text{CH}_3\text{COCH}_3 + \ldots \text{I}_2 + \ldots \text{OH}^- \longrightarrow \ldots \text{CH}_3\text{COO}^- + \ldots \text{H}_2\text{O} + \ldots \text{I}^- + \ldots$

(c(vii))[1]

State one observation that can be made in the reaction in (c)(vi).

Worked solution & mark scheme

This 16-mark question has a full step-by-step worked solution and mark scheme. One marking point: Volatility gets lower down the group

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