Organic chemistry question

[Alaa1984]

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Hi,
Which H is the most acidi:
1. Carboxylic acid
2. Hydrogen coming out of a carbonyl group
3. Alpha hydrogen
4. Phnol
Can you please tell me the order of increasing acidity?

The second question is:
How can we tell if a sugar is a reducing or a non reducing sugar?
Thanks,

 

[DAT Destroyer]

Hi,
Which H is the most acidi:
1. Carboxylic acid
2. Hydrogen coming out of a carbonyl group
3. Alpha hydrogen
4. Phnol
Can you please tell me the order of increasing acidity?

The second question is:
How can we tell if a sugar is a reducing or a non reducing sugar?
Thanks,

Carboxy acid is most acidic...Pka value around 5...... double alpha on a carbonyl around 9.......phenol around 10.........aldehyde or ketone alpha hydrogen around 17 and 18 respectively.

For the second question.....This is VERY important.....a reducing sugar gives a positive Tollens, Benedicts, and Fehlings test......and will mutarotate when put in solution. The sugar must have the hemiacetal group for this to occur. This group can open and close....thus converting an alpha sugar into a beta sugar.

Consult any organic text to verify where this linkage occurs.

Hope this helps.

Dr Jim Romano