Q23 / 180 · COMEDK 2025 (10 May Shift 3) · Chemistry
The oxidation number of potassium in $\mathrm{K}_2 \mathrm{O}, \mathrm{K}_2 \mathrm{O}_2$ and $\mathrm{KO}_2$ respectively are:
- A$+1,+2,+1$
- B$+1,+2,+4$
- C$+2,+1,+1$
- Correct answerD$+1,+1,+1$
Solution
In $\mathrm{K}_2 \mathrm{O}$, the oxidation number of oxygen is $-2$. Let the oxidation number of potassium be $x$. Then $2x + (-2) = 0$, which gives $x = +1$.
In $\mathrm{K}_2 \mathrm{O}_2$, the oxygen is in the peroxide form, $\mathrm{O}_2^{2-}$, where the oxidation number of oxygen is $-1$. Let the oxidation number of potassium be $x$. Then $2x + 2(-1) = 0$, which gives $2x = 2$, so $x = +1$.
In $\mathrm{KO}_2$, the oxygen is in the superoxide form, $\mathrm{O}_2^{-}$, where the oxidation number of oxygen is $-0.5$. Let the oxidation number of potassium be $x$. Then $x + 2(-0.5) = 0$, which gives $x - 1 = 0$, so $x = +1$.
Thus, the oxidation number of potassium in all three compounds is $+1$.
Answer: $+1,+1,+1$
In $\mathrm{K}_2 \mathrm{O}_2$, the oxygen is in the peroxide form, $\mathrm{O}_2^{2-}$, where the oxidation number of oxygen is $-1$. Let the oxidation number of potassium be $x$. Then $2x + 2(-1) = 0$, which gives $2x = 2$, so $x = +1$.
In $\mathrm{KO}_2$, the oxygen is in the superoxide form, $\mathrm{O}_2^{-}$, where the oxidation number of oxygen is $-0.5$. Let the oxidation number of potassium be $x$. Then $x + 2(-0.5) = 0$, which gives $x - 1 = 0$, so $x = +1$.
Thus, the oxidation number of potassium in all three compounds is $+1$.
Answer: $+1,+1,+1$
Hence, the correct answer is option: 'D'.