Introduction:
Aldehydes and ketones are the simple organic compounds known as carbonyl compounds. They encompass a carbonyl group.
Structures of Aldehyde and Ketones:
In aldehydes, the carbonyl group consists of a hydrogen atom attached to it altogether by either a second hydrogen atom or a hydrocarbon group which might be an alkyl group or one having a benzene ring.
For illustration:
Fig: Structures of Aldehyde and Ketones
All the structures above encompass precisely the similar end to the molecule; all that differs is the complexity of the other group attached.
In ketones the carbonyl group consists of two hydrocarbon groups attached. These could either be alkyl group or one having alkyl group and one aromatic ring or two aromatic rings.
Fig: Ketones having carbonyl group
IUPAC Nomenclature of Aldehydes and Ketones:
Aldehydes:
The term Aldehyde are derived from the root hydrocarbon by adding the suffix '-al' to substitute '-e' from the corresponding alkane. For illustration:
Fig: Aldehydes
Where there are other substituents on the carbon chain, they are named by using the prefix (es) with the numbering of carbon from the carbonyl carbon.
Ketones:
Ketones are named as derivatives of the corresponding alkane by the suffix '-one' substituting the '-e' from the corresponding alkane. For illustration,
Fig: Ketones
The position of the carbonyl group on the carbon chain for the isomeric ketones is pointed out by numbers, for illustration: Pentan-3-one
Bonding and reactivity:
The carbon-oxygen double bond is extremely highly polar. This is due to the reason that oxygen is far more electronegative than carbon and therefore consists of a strong tendency to pull electrons in a carbon-oxygen bond towards itself making it partly negative and the carbon partly positive.
Fig: Bonding and reactivity
Physical properties of aldehydes and ketones:
The simple aliphatic aldehydes and ketones are all colourless liquid at 20oC by the exception of methanal which is a gas (that is, boiling point: 21oC). Ethanal consists of a boiling point of 20oC that means, it boils at close to room temperature. The boiling points rise as the molecules get bigger.
The size of the boiling point is governed through the strength of the Van der Waal's force of attraction that becomes stronger as the molecules get longer and encompass more electrons. This describes why the boiling point increases as the number of carbon atoms in the chain increases.
The functional group (that is, carbonyl group) is polar because of an important difference in the electronegativity of the carbon oxygen atoms. Because of the high polarity in their molecules, carbonyl compounds have higher boiling points than alkanes of alike molecular masses, however much lower than those of alcohols of similar molecular masses due to carbonyl compounds unlike alcohols don't encompass intermolecular hydrogen bonding.
Table: Boiling Point of Propane, Ethanal and Ethanol
Molecule Type Boiling Point (oC)
CH3CH2CH3 alkane -42
CH3CHO aldehyde -21
CH3CH2OH alcohol 78
It will be noted that in the above table, the aldehyde (by dipole-dipole attractions and also Van der Waals forces) consists of a boiling point higher than the likewise size alkane which only consists of forces of attraction.
The density of simple aldehydes and ketones are lower than that of water and rises as the relative molecular mass increases. Aromatic aldehydes and ketones are somewhat denser than water.
Aldehydes and ketones having short hydrocarbon chains are miscible with water while those by long hydrocarbon chains are insoluble. Lower members of the carbonyl compounds can form hydrogen bonds with water molecule and therefore they have reasonably high solubility in water compared by hydrocarbons of similar molecular masses. Carbonyl compound having carbon atoms of five and above and aromatic compounds which takes place in nature are insoluble in the water as hydrophobic character of the alkyl chains and aromatic rings outweighs the polar character of the carbonyl group.
Tutorsglobe: A way to secure high grade in your curriculum (Online Tutoring)
Expand your confidence, grow study skills and improve your grades.
Since 2009, Tutorsglobe has proactively helped millions of students to get better grades in school, college or university and score well in competitive tests with live, one-on-one online tutoring.
Using an advanced developed tutoring system providing little or no wait time, the students are connected on-demand with a tutor at www.tutorsglobe.com. Students work one-on-one, in real-time with a tutor, communicating and studying using a virtual whiteboard technology. Scientific and mathematical notation, symbols, geometric figures, graphing and freehand drawing can be rendered quickly and easily in the advanced whiteboard.
Free to know our price and packages for online Chemistry tutoring. Chat with us or submit request at [email protected]
tutorsglobe.com immunity assignment help-homework help by online immunology tutors
www.tutorsglobe.com offers biophysical chemistry homework help, biophysical chemistry assignment help, online tutoring assistance, physical chemistry solutions by online qualified tutor's help.
www.tutorsglobe.com offers resonance homework help, resonance assignment help, online tutoring assistance, organic chemistry solutions by online qualified tutor's help.
www.tutorsglobe.com offers sample assignments and homework help in operation research for solving problems under solving two-person and zero-sum game
Sorting algorithm and their types including the key concepts of Bubble Sort, Quick Sort, Quick sort pseudo code, Quick Sort for C, Multi field sorting, advanced sorting technique, Linear-time Sorting, Assignment help and Homework help.
tutorsglobe.com dairy assignment help-homework help by online applied biology tutors
www.tutorsglobe.com offers structured analysis homework help, assignment help, case study, writing homework help, online tutoring assistance by Software Engineering tutors.
tutorsglobe.com cobb-douglas utility functions assignment help-homework help by online choice and utility maximization tutors
tutorsglobe.com cost-push inflation assignment help-homework help by online inflation and deflation tutors
get premium sas assignment help service by the skilled and qualified tutors and secure top grades at affordable price range!
tutorsglobe.com functioning of male reproductive system assignment help-homework help by online reproduction tutors
tutorsglobe.com birth control assignment help-homework help by online reproduction tutors
tutorsglobe.com prevention of establishment of organism assignment help-homework help by online prophylaxis of diphtheria tutors
Growlers are also given with meters (ammeter/milli-volt) on the panel with variable resistance.
tutorsglobe.com criticism of adam smiths definition assignment help-homework help by online adam smiths definition tutors
1950278
Questions Asked
3689
Tutors
1450296
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!