Question

Is fructose aldohexose?

Answer 1

We need to know that the sweetness is generally associated with mono and disaccharides; this property is not alone found in sugars only. Several other kinds of organic compounds have been synthesized that are used as sweetening agents which is usually termed as artificial sweeteners or high intensity sweeteners.

Complete answer:
Before starting this question let’s frost know what is fructose? D-Fructose is the most abundant ketohexose. Note that from the third through the sixth carbon atoms, its structure is the same as that of glucose. It occurs, along with glucose and sucrose, in honey (which is $40\%$ fructose) and sweet fruits. Fructose is also referred to as levulose because it has a specific rotation that is strongly levorotatory $\left( { - 92.4^\circ } \right)$.It is the sweetest sugar, being $1.7$ times sweeter than sucrose, although many non sugars are several hundred or several thousand times as sweet.
We can draw the structure of fructose as,

This is a structure of D-(-) fructose. As you can see in the structure there is a ketonic group present thus we can say that is a ketohexose and not aldohexose. Glucose and galactose are aldohexose since they have an aldehyde group present in them.
The structure of D-(+)-Glucose can be represented as, as seen in the structure there is presence of an aldehydic group instead of ketonic group thus it is an aldohexose.

Note:
We need to know that hexose is a word used for the number of carbon atoms in a particular sugar. Sugar comes under the category of carbohydrates and they are generally detectable due to the charging sound produced when we heat the sugar on flame, also known as flame test. Since sugar contains six carbon atoms thus they are called hexose.