Decomposition of ${\mathrm{H}}_2{\mathrm{O}}_2$ is retarded by :

$2{\mathrm{H}}_2{\mathrm{O}}_2\left(\mathrm{l}\right)\to 2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)$

Decomposition of hydrogen peroxide is retarded by acetanilide.

Acetanilide slows down ${\mathrm{H}}_2{\mathrm{O}}_2$'s breakdown. Small concentrations of acid, glycerol, and alcohol also slow down the decomposition of hydrogen peroxide, in addition to acetanilide.

In the presence of light, hydrogen peroxide also breaks down, but more slowly. It is kept in a dark bottle in a mildly acidic solution with a stabilizer to prevent it from interacting with other substances.