Difference Between Polyhydroxy Aldehydes and Polyhydroxy Ketone

Polyhydroxy aldehydes are organic compounds containing many hydroxyl groups (-OH) and an aldehyde group (-C(=O)H) while Polyhydroxy ketones are organic compounds containing many hydroxyl groups and a ketone group (-C(=O)-). ... However, both these compounds have carbonyl groups.

1. What are polyhydroxy aldehydes and ketones?
2. What is the difference between an aldehyde and a ketone?
3. Why are carbohydrates known as polyhydroxy aldehydes and ketones?
4. What molecules are defined as polyhydroxy aldehydes or polyhydroxy ketones or the compounds that can be hydrolyzed to either of them?
5. What are polyhydroxy aldehydes?
6. What is a polyhydroxy alcohol?
7. Why ketones are not oxidised?
8. Why can't ketones be oxidised further?
9. Why ketones do not give Fehling test?
10. What are 4 types of carbohydrates?
11. What are the 3 classes of carbohydrates?
12. What are the classes of carbohydrates and give examples?

What are polyhydroxy aldehydes and ketones?

We define polyhydroxy aldehydes or polyhydroxy ketones are those carbon compounds, in which the number of carbon atoms is high, where more than one carbon atom has an alcohol or hydroxyl group (−OH) group and the terminal carbon has either the aldehyde (−CHO) or the ketone (−C=O) group.

What is the difference between an aldehyde and a ketone?

You will remember that the difference between an aldehyde and a ketone is the presence of a hydrogen atom attached to the carbon-oxygen double bond in the aldehyde. Ketones don't have that hydrogen. ... Aldehydes are easily oxidized by all sorts of different oxidizing agents: ketones are not.

Why are carbohydrates known as polyhydroxy aldehydes and ketones?

The simplest carbohydrate molecules possess an aldehyde or ketone group and a hydroxyl group on every carbon atom except the one involved in the carbonyl group. As a result, carbohydrates are defined as aldehyde (the aldoses) or ketone (the ketoses) derivatives of polyhydroxy alcohols and their reaction products.

What molecules are defined as polyhydroxy aldehydes or polyhydroxy ketones or the compounds that can be hydrolyzed to either of them?

All carbohydrates consist of carbon, hydrogen, and oxygen atoms and are polyhydroxy aldehydes or ketones or are compounds that can be broken down to form such compounds. Examples of carbohydrates include starch, fiber, the sweet-tasting compounds called sugars, and structural materials such as cellulose.

What are polyhydroxy aldehydes?

Polyhydroxy aldehydes or ketones are molecules with more than one hydroxyl group (−OH), and a carbonyl group (C=O) either at the terminal carbon atom (aldose) or at the second carbon atom (ketose) are called carbohydrates.

What is a polyhydroxy alcohol?

Compounds that possess more than one alcohol group are called polyhydroxy alcohols. ... Two simple and important polyhydroxy alcohols are ethylene glycol and glycerol. Examples: Blood sugar is a polyhydroxy compound with 5 alcohol groups.

Why ketones are not oxidised?

Oxidation of Ketones

Because ketones do not have hydrogen atom attached to their carbonyl, they are resistant to oxidation. Only very strong oxidizing agents such as potassium manganate(VII) (potassium permanganate) solution oxidize ketones.

Why can't ketones be oxidised further?

Because ketones don't have that particular hydrogen atom, they are resistant to oxidation. Only very strong oxidising agents like potassium manganate(VII) solution (potassium permanganate solution) oxidise ketones - and they do it in a destructive way, breaking carbon-carbon bonds.

Why ketones do not give Fehling test?

The bistartratocuprate(II) complex in Fehling's solution is anoxidizing agent and the active reagent in the test. The compound to be tested is added to the Fehling's solution and the mixture is heated. Aldehydes are oxidized, giving a positive result, but ketones do not react, unless they are alpha-hydroxy-ketones.

What are 4 types of carbohydrates?

Carbohydrates are divided into four types: monosaccharides, disaccharides, oligosaccharides, and polysaccharides.

What are the 3 classes of carbohydrates?

There are three main types of carbohydrates:

• Sugars. They are also called simple carbohydrates because they are in the most basic form. ...
• Starches. They are complex carbohydrates, which are made of lots of simple sugars strung together. ...
• Fiber. It is also a complex carbohydrate.

What are the classes of carbohydrates and give examples?

The simplest carbohydrates are the three carbon dihydroxyacetone and trioses glyceraldehyde. They are further classified into glucose, fructose, galactose, and mannose.
...
1. Monosaccharides: