A reaction between M and Cl2 gives the only product MxCly. The following results are obtained under — Physical Chemistry Chemistry Question
Compound Identification and Related Chemistry
A reaction between M and Cl2 gives the only product MxCly. The following results are obtained under various conditions:
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What is the chemical formula of MxCly? Identify M.
Model Answer
MCl3 and M = Al
Theoretically, the maximum amount of the product is obtained when the mole fraction of M and Cl2 are in the correct stoichiometric ratio. Based on the experiments, M : Cl2 = 0.4 : 0.6 or 2/3 is the stoichiometric ratio needed to form MxCly. Thus, the equation is as follows:
2 M + 3 Cl2 → 2 MCl3.
Thus, the chemical formula of MxCly = MCl3
Since 0.4 mol of M generates 0.4 mol of MCl3, the molar mass of MCl3 and atomic mass of M can be derived:
Molar mass of MCl3 = 53.3 g / 0.40 mol = 133 g mol-1
Atomic mass of M = 133 – (3 * atomic mass Cl) = 133.3 – (3 * 35.45) = 26.9 g mol-1
Thus: M = Al
Write balanced chemical equations of:
(i) complete hydrolysis of MxCly
(ii) MxCly + H2SO4
Model Answer
(i) AlCl3 + 3 H2O → Al(OH)3 + 3 HCl
(ii) 2 AlCl3 + 3 H2SO4 → Al2(SO4)3 + 6 HCl
At certain temperatures, MxCly exists in equilibrium as a dimer:
Draw a chemical structure of the dimer.
Model Answer
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