Sugars Question.

[mattg443]

Hi.

When glucose is dissolved into water it forms d-glucose where it is equilibrium with its alpha and beta glucose isomers since the end carbon can rotate. (yes?)

Just wondering if it was possible that some of the middle carbons rotated and then some galactose was produced (since it differs only in the position of OH groups in the ring).

Any thoughts?

[Borek]

Carbon rotation is not enough to change one into another.

[mattg443]

But isn't the only difference between glucose and galatose the positioning of the OH/H groups off the carbons? Which is a rotation isn't it?

Galactose: http://img.tfd.com/mgh/ceb/thumb/Structural-formula-for-x3b1-d-galactose.jpg
Glucose :http://drpinna.com/wp-content/uploads/2010/08/glucose.gif

[Borek]

No, it is a chiral carbon.

[mattg443]

Okay, haven't come across that yet. But thanks.
Another related question - in the reducing sugars test, using beddedicts solution, the reaction involves OH- ions, yet Bennidicts solution is CuSO4. Do the OH- ions come from the self ionisation of water?
Thanks (im only in high school, so sorry if my questions seem basic (pun not intended))