Question

Name the formula that does not not fit into the formula ${{\mathbf{C}}_{\mathbf{x}}}{\left( {{{\mathbf{H}}_2}{\mathbf{O}}} \right)_{\mathbf{y}}}$, but it has a carbohydrate.

Answer 1

Hint: Carbohydrates consist of carbon, hydrogen and oxygen. They are naturally occurring carbonyl compounds (aldehydes or ketones) which also contain hydroxyl groups. They are also referred to as saccharides.

Complete Step by step answer: Carbohydrates, as we know it can be a single molecule or a bigger molecule formed by the condensation of smaller carbohydrates with simultaneous elimination of water. On hydrolysis, they broke down into smaller compounds from which they are formed.
Carbohydrates are classified depending upon the number of basic carbohydrate units produced on acid hydrolysis. They are monosaccharides, disaccharides, oligosaccharides and polysaccharides.
Monosaccharides are the simplest of carbohydrates which cannot be further hydrolyzed.
Disaccharides, when two monosaccharides are joined, we can say that it disaccharides.
Oligosaccharides are compound sugars which yield 2-10 molecules of the same or different monosaccharides on hydrolysis.
Polysaccharides can contain more than 10 monosaccharides units. It can be a hundred units of sugar length.

Here in question we have given a monosaccharide with the general formula of ${{\text{C}}_{\text{x}}}{\left( {{{\text{H}}_2}{\text{O}}} \right)_{\text{y}}}$. Only rhamnose has the molecular formula which does not fit into this general formula. The molecular formula of rhamnose is ${C_6}{H_{12}}{O_5}$. We cannot write this into its general formula. Hence we can say that rhamnose does not fit into the general formula of monosaccharides.

Note: Here, we saw that there are carbohydrates which does not fit into the general formula but there are compounds which fit into this general formula but they are not carbohydrates. Examples are formaldehyde $\left( {HCHO} \right)$ and acetic acid $\left( {C{H_3}COOH} \right)$. Formaldehyde are known as glycolaldehyde, which means not a true sugar.