Chemistry 9701/42 May June 2014 | Cambridge AS Level Past Papers With Mark Scheme

1. Transition metal ion properties and color formation; electron arrangements in Fe, Fe²⁺, and Zn²⁺ ions, and explanation of color differences due to d-orbital splitting and electron transitions.

2. Coordination chemistry of Cu²⁺ with concentrated HCl and NH₃; species responsible for yellow color, ligand exchange reactions, and identification of intermediate and final species.

3. Role of Fe²⁺ and Fe³⁺ ions as catalysts in reactions involving KI and K₂S₂O₈; overall reaction, catalytic mechanism, and equations illustrating the redox cycle.

4. Solubility and electrochemical properties of PbCl₂; calculation of solubility product (Ksp), electrode potentials, and lattice energy determination with comparisons to PbBr₂.

5. Structural and optical isomerism in esters; hydrolysis producing ethanoic acid, differences in Ka values of ethanoic acid, ethanol, and chloroethanoic acid, and calculation of pH for ethanoic acid solutions.

6. Electrophilic reactions of benzene and derivatives; reaction mechanisms for bromination, nitration, and synthesis of substituted benzoic acids with conditions and intermediate structures.

7. Analysis of amino acids and protein-related reactions; electrophoresis separation, paper chromatography, and interpretation of codons in protein synthesis errors leading to mutations.

8. Polymer chemistry involving addition and condensation reactions; biodegradability, renewable sources for polymer monomers, and identification of intermolecular forces in polymer chains.