--%>
Assignment Help - homework help

What is cannizaro reaction? Explain with example.

Aldehydes which do not have 606_amines with aldehydes3.png -hydrogen atom, such as formaldehyte and benzaldehyte, when heated with concentrated (50%)alkali solution, give a mixture of alcohol and the salt of a carboxylic acid.
1587_cannizaro reaction.png 
In this reaction, the aldehyde undergoes disproportionate. It implies that one molecule of aldehydes is oxidized to carboxylic acid and the other is reduced to alcohol. Ketones do not provide this reaction.
 The reaction is also possible in all compounds which lack 606_amines with aldehydes3.png -hydrogen atom. For example,

1131_cannizaro reaction1.png 


It must be noted that in crossed Cannizzaro's reaction, when an aldehydes is treated with formaldehyde and aqueous basic solution then it is formaldehyde that undergoes oxidation.
2028_cannizaro reaction2.png 

Compounds containing two carbonyl groups undergo internal Cannizzaro's reaction.
738_cannizaro reaction3.png 
On the other hand, aldehydes containing 606_amines with aldehydes3.png -hydrogen atoms when heated with concentrated alkali give brown resinous mass.
1335_cannizaro reaction4.png

   Related Questions in Chemistry

  • Q : Colligative properties give atleast two

    give atleast two application of following colligative properties

    		•
  • Q : What is Spectroscopy? This is a very

    This is a very important aspect of Physical Chemistry in which knowledge of the size, shape, rigidity and electronic structure of molecules deduced from the experimental methods treated here goes hand in hand with the theoretical approaches of chemical reactions. Spec

    		•
  • Q : HCl polarity Illustrate HCl is polar or

    Illustrate HCl is polar or non-polar?

    		•
  • Q : What is Ideal Mixtures Ideal mixing

    Ideal mixing properties can be recognized in the formation of an ideal gas mixture from ideal gases. Consider the formation of a mixture of gases i.e. a gaseous solution, from two mixtures of pure gases. A useful characterization of an ideal mixture, or soluti

    		•
  • Q : Problem on physical and thermodynamic

    The shells of marine organisms contain calcium carbonate CaCO3, largely in a crystalline form known as calcite. There is a second crystalline form of calcium carbonate known as aragonite. Physical and thermodynamic properties of calcite and aragonite at 298

    		•
  • Q : Question based on strength of solution

    Help me to go through this problem. On dissolving 1 mole of each of the following acids in 1 litre water, the acid which does not give a solution of strength 1N is: (a) HCl (b) Perchloric acid (c) HNO3 (d) Phosphoric acid

    		•
  • Q : Mole fraction and Molality Select the

    Select the right answer of the following question.What does not change on changing temperature : (a) Mole fraction (b) Normality (c) Molality (d) None of these

    		•
  • Q : What are the chemical properties of

    Haloalkanes are extremely reactive category of aliphatic compounds. Their reactivity is due to the presence of polar carbon-halogen bond in their mole

    		•
  • Q : Define tripod and its use Illustrate a

    Illustrate a tripod? And how it’s used?

    		•
  • Q : Real vapour pressure Choose the right

    Choose the right answer from following. The pressure under which liquid and vapour can coexist at equilibrium is called the : (a) Limiting vapour pressure (b) Real vapour pressure (c) Normal vapour pressure (d) Saturated vapour pressure

    		•