due to the strongly alkaline reaction conditions, aldehydes that have alpha hydrogen atom(s) instead undergo deprotonation there, leading to enolates and possible aldol reactions. under ideal conditions the reaction produces only 50% of the alcohol and the carboxylic acid (it takes two aldehydes to produce one acid and one alcohol). to avoid the low yields, it is more common to conduct the crossed cannizzaro reaction, in which a sacrificial aldehyde is used in combination with a more valuable chemical. in this variation, the reductant is formaldehyde, which is oxidized to sodium formate and the other aldehyde chemical is reduced to the alcohol. in this scenario, each of the two separate aldehydes can be converted completely to its corresponding product rather than losing 50% of a single reactant to each of two different products. thus, the yield of the valuable chemical is high, although the atom economy is still low.