--%>
Assignment Help - homework help

Explain alcohols and phenols in organic chemistry.

Alcohols and phenols are the compounds containing one or more hydroxyl groups (- OH). The alcohols contain the -OH group attached to alkyl group whereas in phenols, the -OH group is attached to aromatic ring. These are classified as mono-, di- and trihydric alcohols or phenols according to the number of -OH groups contained in their molecules. Some examples of mono-, di- and trihydric alcohols and phenols are as follows:

    Alcohols

2399_alcohol and phenol.png 

It may be noted that the aromatic compounds in which -OH group is not directly attached to benzene ring are not phenols but are called aromatic alcohols. These may also be called as aryl derivatives of aliphatic alcohols. When four or more hydroxyl groups are present, they are called polyhydric alcohols or polyhydric phenols.

Monohydric alcohols may be further classified according to the hybrid state of the carbon atom to which the -OH group is attached.
    
Compounds containing Csp3 ) -OH bond

In this type of alcohols, the -OH group is attached to a sp3 hybridised carbon atom. They are further classify as follows:

Primary (1°), secondary (2°) and tertiary (3°) alcohols

Monohydric alcohols are classified as primary, secondary or tertiary alcohols depending upon whether the hydroxyl group is attached to a primary, secondary or tertiary carbon atom. For instance,

1240_alcohol and phenol1.png 

Allylic alcohols: in allylic alcohols, the -OH group is attached to a sp3-hybridised carbon next to the carbon-carbon double bond, that is to an allylic carbon. For instance,

2066_alcohol and phenol2.png 

Benzylic alcohols: in benzlylic alcohols, the -OH group is attached to a sp3 -hybridised carbon atom next to an aromatic ring. Allylic and benzylic alcohols can be secondary, primary or tertiary.
    
Compounds containing Csp3 )-OH bond:

These alcohols include -OH group bonded to a carbon-carbon double bond i.e. to a vinylic carbon or to an aryl carbon. For example, vinylic alcohols and phenols belong to this class of compounds.

   Related Questions in Chemistry

  • Q : Composition of the vapour Choose the

    Choose the right answer from following. An ideal solution was obtained by mixing methanol and ethanol. If the partial vapour pressure of methanol and ethanol are 2.619KPa and 4.556KPa respectively, the composition of the vapour (in terms of mole fraction) will be: (

    		•
  • Q : Problem on Osmotic Pressure of solution

    The osmotic pressure of a 5% solution of cane sugar at 150oC  is (mol. wt. of cane sugar = 342)(a) 4 atm (b) 3.4 atm (c) 5.07 atm (d) 2.45 atmAnswer: (c) Π = (5 x 0.0821 x 1000 x 423)/(342 x 100) = 5.07 atm

    		•
  • Q : Describe physical adsorption and its

    When the forces of attraction existing between adsorbate and adsorbent are van der Waal's forces, the adsorption is called physical adsorption. This type of adsorption is also known as physisorption or van der Waal's adsorption. Since the forces existing between adsorbent and adsorbate are very w

    		•
  • Q : Dipole moment of chloro-octane Describe

    Describe the dipole moment of chloro-octane in brief?

    		•
  • Q : How can enzymes act as catalyst?

    Enzymes are complex proteinous substances, produced by living bodies, such as act as catalysis in the physiological reactions. The enzymes are, also called biochemical catalysts and the phenomenon is known as bio-chemical catalysis because numerous reactions that occur the bodies of animals and p

    		•
  • Q : Neutralization of benzoic acid Choose

    Choose the right answer from following. How many grams of NaOH will be required to neutralize 12.2 grams of benzoic acid : (a) 40gms (b) 4gms (c)16gms (d)12.2gms

    		•
  • Q : How to establish nomenclature for

    In the common chemistry terminologies, aliphatic halogen derivatives are named as alkyl halides. The words, n-, sec-, tert-, iso-, neo-, and amyl are

    		•
  • Q : Acid Solutions Choose the right answer

    Choose the right answer from following. Volume of water needed to mix with 10 ml 10N NHO3 to get 0.1 N HNO3: (a) 1000 ml (b) 990 ml (c) 1010 ml (d) 10 ml

    		•
  • Q : Atmospheric pressure Give me answer of

    Give me answer of this question. The atmospheric pressure is sum of the: (a) Pressure of the biomolecules (b) Vapour pressure of atmospheric constituents (c) Vapour pressure of chemicals and vapour pressure of volatile (d) Pressure created on to atmospheric molecules

    		•
  • Q : Question based on vapour pressure and

    Benzene and toluene form nearly ideal solutions. At 20°C, the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The parial vapour pressure of benzene at 20°C for a solution containing 78g of benzene and 46g of toluene in torr is: (a) 50 (b)

    		•