Identify the following statements as either True or False.

1) Carbohydrates are polyhydroxy aldehydes, ketones, or compounds that yield polyhydroxy aldehydes or ketones upon hydrolysis.
2) Monosaccharides exist as cyclic structures containing functional groups such as hydroxyl groups, acetal (ketal), and hemiacetal (hemiketal).
3) A carbohydrate can be classified as a monosaccharide, disaccharide, or polysaccharide.
4) Disaccharides exist as cyclic structures that only contain hemiacetal (or hemiketal) groups.

Carbohydrates are polyhydroxy aldehydes, ketones, or compounds that yield polyhydroxy aldehydes or ketones upon hydrolysis. FALSE

Monosaccharides exist as cyclic structures containing functional groups such as hydroxyl groups, acetal (ketal), and hemiacetal (hemiketal). TRUE

A carbohydrate can be classified as a monosaccharide, disaccharide, or polysaccharide TRUE

Disaccharides exist as cyclic structures that only contain hemiacetal (or hemiketal) groups. FALSE

Explanation:

carbohydrates consists of a long cyclic chain of monosaccharides. They are polysaccharides and exist in the cyclic structure. It is only the individual monosaccharides that contain the aldehyde or ketone group as the case may be.

When completely hydrolysed monosaccharides are formed from polysaccharides which are cyclic hemiacetals and acetals containing the hydroxyl functional group.

Carbohydrates containing only one sugar unit is a monosaccharide, if it contains two sugar units it is a diasaccharide, it contains more than two sugar units it is a polysaccharide.

Diasaccharides such as fructose also contain hemiacetal or hemiketal groups and -OH groups also.

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.