Given the half-cell reaction, 2Br \(\rightarrow\) Br 2 , how many moles of electron will

Explanation

First, we need to determine the number of moles of bromine (Br₂) that are produced. We can do this by using the molar volume of gas at standard temperature and pressure (s.t.p.), which is 22.4 dm³/mol.

To find the moles of Br₂, we can use the formula:

\[\text{moles of Br}_2 = \frac{\text{volume of Br}_2}{\text{molar volume of gas at s.t.p.}}\]

Plugging in the given values:

\[\text{moles of Br}_2 = \frac{0.56 \ \text{dm}^3}{22.4 \ \text{dm}^3/\text{mol}} = 0.025 \ \text{mol}\]

Now, we need to determine the number of moles of electrons required for the half-cell reaction. The balanced half-cell reaction is:

2Br^- \(\rightarrow\) Br₂ + 2e^-

This means that 2 moles of electrons are required for every 1 mole of Br₂ produced. So, we can find the moles of electrons needed by multiplying the moles of Br₂ by 2:

\[\text{moles of electrons} = 0.025 \ \text{mol} \times 2 = 0.05 \ \text{mol}\]

Therefore, 0.05 moles of electrons will be required to produce 0.56 dm³ of bromine at s.t.p., making Option A the correct answer.