Phosphorus and chlorine are elements in Period 3 of the Periodic Table.

1. (a)Chlorine forms three different compounds with phosphorus. The most common compounds are PCl3 and PCl5.
2. (a)(i)Complete Table 1.1. Table 1.1 compound | oxidation number of P | oxidation number of Cl ---|---|--- PCl3 | | PCl5 | | [2][2]
3. (a)(ii)In a closed system, PCl3 and PCl5 exist in an equilibrium mixture as shown in reaction 1. reaction 1 PCl3(l) + Cl2(g) ⇌ PCl5(s) ΔH = –124 kJ mol–1 Deduce two conditions that favour the production of PCl5 in reaction 1. 1 2 [2][2]
4. (a)(iii)The third compound of phosphorus and chlorine, W, has a relative molecular mass, Mr, between that of PCl3 and PCl5. The compound contains 69.6% by mass of chlorine. Determine the molecular formula of W. molecular formula of W = [2][2]
5. (a)(iv)W is a liquid at room temperature and pressure. It reacts vigorously with water to form an acidic solution. Suggest the structure and bonding in W. Explain your answer. [2][2]
6. (b)[Figure 1.1] shows a reaction scheme involving P4 and Cl2. P4 ---Cl2(g) reaction 2---> PCl5 ---reaction 6---> C ---Cl---> ClCH2CH2Cl excess O2(g) reaction 3 | H2O reaction 4 A(s) ---H2O reaction 5---> B(aq) [Figure 1.1]
7. (b)(i)Suggest what is observed in reaction 2. [1][1]
8. (b)(ii)Predict the shape of a molecule of PCl5. [1][1]
9. (b)(iii)Write an equation for the formation of A in reaction 3. [1][1]
10. (b)(iv)Name B, which is formed in both reactions 4 and 5. [1][1]
11. (b)(v)Draw the structure of C, used in reaction 6. [1][1]
12. (c)1,2-dichloroethane, ClCH2CH2Cl, reacts with NaOH to produce an unsaturated compound, C2H3Cl, as shown in reaction 7. reaction 7 ClCH2CH2Cl + NaOH → C2H3Cl + H2O + NaCl
13. (c)(i)State what is meant by unsaturated. [1][1]
14. (c)(ii)State the conditions for reaction 7. [1][1]
15. (d)Compound D contains carbon, hydrogen and chlorine only. [Figure 1.2] shows the mass spectrum of D. [Figure 1.2]
16. (d)(i)Explain the relative abundance of peaks 1 and 2 in the mass spectrum in [Figure 1.2]. [1][1]
17. (d)(ii)Suggest the structure of D. [1][1]

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