A series of reactions for phosphorus and its compounds is shown. P ---excess Cl2 reaction 1---> PCl5 ---H₂O reaction 2---> H3PO4 ---NH3 reaction 3---> (NH4+)(H2PO4¯)

1. (a)(i)State what you would observe in reaction 1.[1]
2. (a)(ii)State the type of reaction that occurs in reaction 2.[1]
3. (a)(iii)H3PO4 can be produced by direct reaction of phosphorus with nitric acid. P + 5HNO3 → H2O + 5NO2 + H3PO4 Use oxidation numbers to show that this reaction is a redox reaction.[2]
4. (b)(i)Reaction 3 is a neutralisation reaction in which NH3 acts as a base. Explain how NH3 acts as a base in reaction 3.[1]
5. (b)(ii)Draw the three-dimensional shape of the ammonium ion, NH₄⁺. Give the bond angle.[1]
6. (b)(iii)State the industrial importance of compounds such as (NH4+)(H2PO4¯).[1]
7. (c)(i)PCl5 can be used to convert alcohols to halogenoalkanes. Write an equation for the reaction of C2H5OH with PCl5 to form C2H5Cl.[1]
8. (c)(ii)State the type of reaction in (i).[1]
9. (c)(iii)Halogenoalkanes can also be prepared by reacting alcohols with hydrogen halides, such as HCl and HI. * HCl is prepared using NaCl and concentrated H2SO4. * HI is prepared by reacting NaI with concentrated H3PO4. Suggest why HI is not prepared by the reaction of NaI with concentrated H2SO4.[2]
10. (c)(iv)The rate of the hydrolysis reaction of halogenoalkanes with NaOH(aq) is dependent on the halogen that is bonded to carbon. State and explain the order of reactivity when NaOH(aq) reacts separately with C2H5Cl, C2H5Br and C2H5I.[2]

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