Chemistry 9701 · AS & A Level · Group 17

Group 17 — practice question

Chlorine is an element that reacts very readily.
(a)[2]

Chlorine reacts with silicon to make silicon(IV) chloride. Describe the appearance of silicon(IV) chloride at room temperature and pressure. State its structure and bonding.

(b)[4]

Samples of magnesium chloride and phosphorus(V) chloride are placed into separate beakers of cold water. Complete Table 3.1. Ignore temperature changes when you consider the observations for these reactions.

(c(i))[1]

State the reagent and conditions needed for sodium chlorate(V) to form from $\text{Cl}_2\text{(g)}$.

(c(ii))[1]

Explain why the reaction in (c)(i) is called a disproportionation reaction. Your answer should mention the relevant species and their oxidation numbers.

(d(i))[1]

State the conditions needed for chlorine to react with methane.

(d(ii))[3]

One of the products in the reaction is $\text{CH}_2\text{Cl}_2$, and this goes on to form $\text{CHCl}_3$. Complete Table 3.2 to show the mechanism details for the formation of $\text{CHCl}_3$ from $\text{CH}_2\text{Cl}_2$.

(e)[1]

$\text{CHCl}_3$ and HF are used to make $\text{CHClF}_2$ in a substitution reaction. Write an equation for this reaction.

(f)[2]

$X$ is a product of the substitution reaction that occurs when $\text{CHClF}_2$ reacts with $\text{Br}_2$. There is only one naturally occurring isotope of fluorine, $^{19}\text{F}$. The mass spectrum of $X$ shows molecular ion peaks at $m/e = 164$, $166$ and $168$. Complete Table 3.3 to show all the molecular ions responsible for each peak.

Worked solution & mark scheme

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