Question

the redox reaction given below occurs in basic solution.
reo₄⁻ + io⁻ → re + io₃⁻
balance the half - reaction:
reo₄⁻ → re
how many electrons are transferred?
?e⁻

Explanation:

Step1: Determine oxidation states

In \( \text{ReO}_4^- \), let the oxidation state of Re be \( x \). Oxygen has an oxidation state of -2. So, \( x + 4(-2) = -1 \). Solving, \( x - 8 = -1 \), so \( x = +7 \). In \( \text{Re} \) (elemental), the oxidation state is 0.

Step2: Calculate electron transfer

The change in oxidation state of Re is from +7 to 0. The number of electrons transferred is the difference in oxidation states. So, \( 7 - 0 = 7 \) electrons are gained (since Re is reduced).

Answer:

7