[JennLyn6]

which of the following will form a brick-red precipitate with benedict's reagent?

propanone vs. propanal

formaldehyde vs. methane

and how do acetal and hemiacetal compare? i said that acetal is any organic compound formed by adding alcohol molecules to aldehyde molecules and hemiacetal is an organic compound usually formed as an intermediate product in the preparation of acetals from aldehydes or ketones. is that right?

[haiph12]

I think
propanone vs. propanal
formaldehyde vs. methane
have the C=O bond
 

[haiph12]

acetal are:     RCH(OR')₂
and hemiacetal are:   RCH(OH)(OR')
and hemicetal are : RCR''(OH)(OR')
and cetal are: RCR''(OR')(OR')