CARBOHYDRATES....plzz explain how the productsa are obtained!!

This might be helpful for you

In case of simple polyhydroxy compounds, for every two adjacent hydroxyl groups, one

mole of HIO4 is used. Therefore, if there are 'n' adjacent hydroxyl groups, ( n-1) moles of

HIO4 would be used. Thus by knowing the number of moles of HIO4 used, the number of

adjacent hydroxyl groups in a molecule can be determined. For example, oxidation of

glycerol uses two moles of HIO4 per mole of glycerol. therefore, it contains three OH

groups.

HOCH2-CHOH-CH2OH + 2 HIO4 .......> HCHO + HCOOH + HCHO

It may be noted that the internal OH groups are oxidized to formic acid during oxidation.

However, in case of polyhydroxy aldehydes or ketones, since oxidation of -CHOH-CHO or -

CH-CH2OH moity requires one mole of HIO4, therefore, number of moles HIO4 used is

equal to number of adjacent OH groups present. For example, oxidation of one mole of

glucose requires five moles of HIO4.

HOCH2-(CHOH)4-CHO + 5 HIO4 ........> 5 HCOOH + HCHO

HOCH2-(CHOH)3-CO-CH2OH + 5 HIO4 ......> 2 HCHO + 3 HCOOH + CO2

From the above discussion, we can say that CO group is oxidised to CO2, CH2OH to HCHO

and CHO,CHOH to HCOOH.

In the given problem three moles of HIO4 are used and the products are two moles of

formic acid , one mole of formaldehyde and one mole of CO2; thus the structure should be

CHO-CHOH-CO-CH2OH