$CH_3CHO+\dfrac{5}{2}O_2\xrightarrow{{t^o}} 2CO_2+2H_2O$
$CH_3CHO+2Cu(OH)_2\xrightarrow{{t^o}} CH_3COOH+Cu_2O+2H_2O$
$CH_3CHO+2AgNO_3+3NH_3+H_2O\to CH_3COONH_4+2Ag+2NH_4NO_3$
$CH_3CHO+H_2\xrightarrow{{Ni, t^o}} C_2H_5OH$
$CH_3CHO+Br_2+H_2O\to CH_3COOH+2HBr$