Question

Which of the following is not a redox rection?

• A. $CaCO _{3} \longrightarrow CaO + CO _{2}$
• B. $O _{2}+2 H _{2} \longrightarrow 2 H _{2} O$
• C. $Na + H _{2} O \longrightarrow NaOH +\frac{1}{2} H _{2}$
• D. $MnCl _{3} \longrightarrow MnCl _{2}+\frac{1}{2} Cl _{2}$

Answer 1

Answer: (A)

$\overset{+2+4-2}{CaCO _{3}} \longrightarrow \overset{+2-2}{CaO} + \overset{+4-2}{CO _{2}}$
Since, the reaction does not involve oxidation and reduction, it is not a redox reaction.