Does Br2/H2O oxidize all aldehydes including carbohydrates?
Aldehydes, including aldoses, are oxidized to their respective carboxylic acids in the presence of $\ce{Br2}$ in $\ce{H2O}$. The reason this reaction is often discussed with carbohydrates is that it is useful for differentiating aldoses from from ketoses, which cannot be further oxidized. A solution of $\ce{Br2}$ and $\ce{H2O}$ will lose its characteristic brown color in the presence of aldoses, but will not in the presence of ketoses.

The general mechanism for the oxidation of an aldehyde under these conditions is:



Though ketones will be able to form a hydrate like aldehydes, no deprotonation can occur to eliminate the bromide ion as we see in aldehydes. Hence no further oxidation can occur.