Msaada,kwa wataalamu wa chemistry tu

barida wakuu nimepata CONCEPT nw

This is because it dissociates partially hence results to approximation i.e
HCOOH--- H+ +HCOO-
(1-x )c xc xc

thx mr mwamala,kwa hiyo inayo dissolve partially ni hiyo carboxylic acid i.e methanoic acid na kupelekea approximation.Nw nmekupata bro na i thnk unamaanisha ili tupate true value lazima i dissolve totally

HEISENBERG said:

thx mr mwamala,kwa hiyo inayo dissolve partially ni hiyo carboxylic acid i.e methanoic acid na kupelekea approximation.Nw nmekupata bro na i thnk unamaanisha ili tupate true value lazima i dissolve totally

Click to expand...

To "dissolve" and to "dissociate" are two different actions, you seem to mix them.
The answer to your question is as follows: Molar mass determination by cryoscopic method gives unexpected result if the substance (whose molar mass is to be determined) either dissociates or associates when dissolved in the solvent. Dissociation leads to lower molar mass value than expected while association leads to higher molar mass value than expected. In polar solvents, such as water, methanoic acid dissociates, i.e., it ionizes partially.
In nonpolar solvents methanoic acid associates, i.e., it dimerizes.

Jamani. Mim ni history, mtanisamehe