${\mathrm{AgNO}}_3+\mathrm{NaOH}\to \mathrm{AgOH}+{\mathrm{NaNO}}_3$

$2\mathrm{AgOH}\to {\mathrm{Ag}}_2\mathrm{O}+{\mathrm{H}}_2\mathrm{O}$

${\mathrm{Ag}}_2\mathrm{O}+4{\mathrm{NH}}_3+{\mathrm{H}}_2\mathrm{O}\to 2\mathrm{Ag}{\left({\mathrm{NH}}_3\right)}_2^{+}+2\stackrel{⊝}{\mathrm{O}}\mathrm{H}$

Tollens' reagent is an alkaline solution of ammoniacal silver nitrate and is used to test for aldehydes. Tollens' test, also known as silver-mirror test, is a qualitative laboratory test used to distinguish between an aldehyde and a ketone. It exploits the fact that aldehydes are readily oxidized (see oxidation), whereas ketones are not.