Final answer:
In the given reaction, when 0.4235 mol of CuCl₂ reacts, 0.2117 mol of I₂ is produced.
Step-by-step explanation:
The reaction given is:
2CuCl2 + 4KI → 2CuI + 4KCl + I2
From the balanced equation, we can see that 2 moles of CuCl2 produce 1 mole of I2.
Therefore, if 0.4235 mol of CuCl2 is used in the reaction, then the number of moles of I2 produced is 0.4235 mol × (1 mole I2 / 2 moles CuCl2) = 0.2117 mol. So the correct answer is (a) 0.2117 mol.