Chemistry 9701/22 Oct Nov 2013 | Cambridge AS Level Past Papers With Mark Scheme

1. VSEPR theory to predict molecular shapes and bond angles for compounds, including TeF₆ with octahedral geometry and F–Te–F bond angles of 90°.
2. Reactions of C₃H₆ isomers (propene and cyclopropane) with chlorine, yielding dichlorinated products; mechanisms include electrophilic addition for propene and substitution for cyclopropane.
3. Chlorine manufacturing via diaphragm cell electrolysis; electrode reactions, material choices for durability, and observed reactions with sodium and phosphorus.
4. Behavior of chlorine in reactions with cold dilute and hot concentrated NaOH; oxidation state changes and identification of products like NaClO and NaClO₃.
5. pH differences in aqueous solutions of MgCl₂ and SiCl₄ due to ionic dissociation versus hydrolysis; reaction equations highlighting acidity from SiCl₄ hydrolysis.
6. Titration of diprotic acid H₂X with NaOH to determine moles, molar mass, and structure of acid R from given structural possibilities.
7. Reagents and conditions for interconversion of weak acids S, T, and U, including Na and Na₂CO₃ reactions with hydroxyl groups to form salts.
8. Combustion reactions of propane and butane in LPG, including equations for complete and incomplete combustion, heat release calculations, and experimental application of enthalpy.
9. Boiling point trends in alkanes explained by van der Waals forces, molecular size, and branching effects; distinction between n-butane and 2-methylpropane.