2(a) Aluminium chloride exists in the form of dimer at room temperature. (i) Draw the Lewis structure of aluminium chloride when it is heated to 1000 °C. (2 marks) (ii) Mr Andrew plans to replace the

2(a) Aluminium chloride exists in the form of dimer at room temperature. (i) Draw the Lewis structure of aluminium chloride when it is heated to 1000 °C. (2 marks) 

(ii) Mr Andrew plans to replace the aluminium oxide used in Hall-Héroult process with aluminium chloride. As Mr Andrew’s colleague, state whether you agree with him. Explain your answer. (3 marks) 

(iii) State your observation when the aqueous solution of aluminium chloride is tested with a blue litmus paper. Explain your answer with the aid of a balanced chemical equation. (4 marks) 

(b) Write the balanced chemical equation(s) involved, if any, when aluminium is used to extract chromium and calcium from chromium(IV) oxide, CrO2 and calcium oxide, CaO, respectively. Provide an explanation if the extraction process is unsuccessful. (3 marks)

(c) Raymond attempts to coat an aluminium key with a protective layer of aluminium oxide via anodisation process. He completes the circuit by connecting the key to the negative terminal and a platinum strip to the positive terminal. Predict whether Raymond’s attempt is successful. Briefly explain your answer. (3 marks)