Question

the redox reaction given below occurs in basic solution.
tco₄⁻ + sn⁺² → tc⁺⁴ + sn⁺⁴
balance the half - reaction:
tco₄⁻ → tc⁺⁴
how many electrons are transferred?
?e⁻

Explanation:

Step1: Determine oxidation state of Tc in reactant and product

In \( \text{TcO}_4^- \), let oxidation state of Tc be \( x \). Oxygen has oxidation state of \(-2\), and overall charge is \(-1\). So, \( x + 4\times(-2)= -1 \), solving gives \( x = +7 \). In product, Tc is \( +4 \). So Tc is reduced (oxidation state decreases from \( +7 \) to \( +4 \)).

Step2: Calculate change in oxidation state

Change in oxidation state per Tc atom: \( 7 - 4 = 3 \). So each Tc atom gains 3 electrons. Since there is 1 Tc atom in the half - reaction, the number of electrons transferred is 3.

Answer:

3