Q7 / 180 · KCET 2014 · Chemistry
A metallic oxide reacts with water to form its hydroxide, hydrogen peroxide and also liberates
oxygen. The metallic oxide could be
oxygen. The metallic oxide could be
- Correct answerA\( \mathrm{O} \mathrm{K} \mathrm{O}_{2} \)
- B\( \mathrm{Na}_{2} \mathrm{O}_{2} \)
- C\( \mathrm{CaO} \)
- D\( \mathrm{Li}_{2} \mathrm{O} \)
Solution
Potassium Superoxide react with water to produce potassium hydroxide, hydrogen peroxide and oxygen. This reaction
takes place at a temperature near \( 0^{\circ} \mathrm{C} \). Whereas, other metal oxide reacts with water but does not produce peroxide.
\( 2 \mathrm{KO}_{2}+2 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{KOH}+\mathrm{H}_{2} \mathrm{O}_{2}+\mathrm{O}_{2} \)
Reaction of other metal
\( \mathrm{Na}_{2} \mathrm{O}_{2}+2 \mathrm{H}_{2} \mathrm{O} \rightarrow 4 \mathrm{NaOH}(a q)+\mathrm{O}_{2}(g) \) \( \mathrm{CaO}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{Ca}(\mathrm{OH})_{2} \) \( \mathrm{Li}_{2} \mathrm{O}+\mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{LiOH} \)
takes place at a temperature near \( 0^{\circ} \mathrm{C} \). Whereas, other metal oxide reacts with water but does not produce peroxide.
\( 2 \mathrm{KO}_{2}+2 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{KOH}+\mathrm{H}_{2} \mathrm{O}_{2}+\mathrm{O}_{2} \)
Reaction of other metal
\( \mathrm{Na}_{2} \mathrm{O}_{2}+2 \mathrm{H}_{2} \mathrm{O} \rightarrow 4 \mathrm{NaOH}(a q)+\mathrm{O}_{2}(g) \) \( \mathrm{CaO}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{Ca}(\mathrm{OH})_{2} \) \( \mathrm{Li}_{2} \mathrm{O}+\mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{LiOH} \)
Hence, the correct answer is option: 'A'.