Chemistry 9701 · AS & A Level · Group 17

Group 17 — practice question

Chlorine is one of the Group 17 elements in the Periodic Table.
(a(i))[1]

Describe the colours of the Group 17 elements from chlorine to iodine at room temperature.

(a(ii))[1]

Describe how the reactivity of chlorine to iodine changes as oxidising agents.

(a(iii))[1]

State the observation when chlorine reacts with hydrogen.

(a(iv))[1]

Explain why the thermal stability of the hydrogen halides falls down the group.

(b(i))[1]

The halogenoalkane $\text{CH}_3\text{CH}_2\text{Cl}$ is formed when chlorine reacts with $\text{C}_2\text{H}_6$ by a free-radical substitution mechanism. Define free radical.

(b(ii))[1]

State the essential condition for chlorine to react with $\text{C}_2\text{H}_6$ at room temperature.

(b(iii))[2]

Write two equations that show the propagation steps in this reaction.

(c(i))[1]

Another halogenoalkane is $\text{CHCl}_3$. $\text{CHCl}_3$ is formed when propanone reacts with $\text{NaClO}$. $\text{NaClO}$ is prepared from chlorine in a disproportionation reaction. Identify a reagent and conditions that can be used to convert chlorine to $\text{NaClO}$.

(c(ii))[1]

Define disproportionation.

(c(iii))[1]

Write numbers in the boxes so that the equation for the reaction of propanone with $\text{NaClO}$ is balanced. $\text{CH}_3\text{COCH}_3 + \boxed{}\,\text{NaClO} \rightarrow \boxed{}\,\text{CHCl}_3 + \boxed{}\,\text{CH}_3\text{COONa} + \boxed{}\,\text{NaOH}$

(c(iv))[2]

Aqueous $\text{AgNO}_3$, dissolved in ethanol, is added to an aqueous solution of $\text{CHCl}_3$. State the observation in this reaction. Explain your answer.

(c)[1]

Write numbers in the boxes to balance the equation for the reaction of propanone with $\text{NaClO}$. $\text{CH}_3\text{COCH}_3 + \square\,\text{NaClO} \rightarrow \square\,\text{CHCl}_3 + \square\,\text{CH}_3\text{COONa} + \square\,\text{NaOH}$

(d)[2]

Aqueous $\text{AgNO}_3$, dissolved in ethanol, is added to an aqueous solution of $\text{CHCl}_3$. State the observation in this reaction. Explain your answer.

Worked solution & mark scheme

This 16-mark question has a full step-by-step worked solution and mark scheme. One marking point: Chlorine: yellow-green; bromine: orange/brown/red; iodine: silver-grey/black

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