Question

X and Y are the number of electrons involved, respectively during the oxidation of I$^-$ to I$_2$ and S$^{2-}$ to S by acidified K$_2$Cr$_2$O$_7$. The value of X + Y is ___.

Hint:

In redox reactions, always balance electrons first to determine the number of electrons transferred accurately.

Answer 1

Correct Answer: 4

Step 1: Oxidation of iodide ion.
\[ 2\mathrm{I^-} \rightarrow \mathrm{I_2} + 2e^- \] Number of electrons involved, $X = 2$.
Step 2: Oxidation of sulfide ion.
\[ \mathrm{S^{2-}} \rightarrow \mathrm{S} + 2e^- \] Number of electrons involved, $Y = 2$.
Step 3: Calculate total electrons transferred.
\[ X + Y = 2 + 2 = 4 \]
Step 4: Final conclusion.
The total number of electrons involved in both oxidations is 4.