Question

Molecular formula ${C_5}{H_{10}}O$ can have which of the following chemical formula??
A. $6 - Aldehyde,\;4 - ketone$
B. $5 - Aldehyde,\;3 - ketone$
C. $4 - Aldehyde,\;3 - ketone$
D. $5 - Aldehyde,\;2 - ketone$

Answer 1

Hint: As we know that Chemical formula is a representation of chemical proportion of the atoms present in a compound or molecule. It indicates the simple numbers of each atom in a molecule. It does not tell exact information about the structure so we can predict the compounds as alcohols, ketones or aldehydes.

Complete step by step answer:
As we know that Molecular formula is representation of chemical proportion of the atoms present in a compound or molecule. It indicates the simple numbers of each atom in a molecule or in other words we can say that it is defined as the formula which gives the actual number of atoms of various elements present in the molecule of the compounds.

We can predict the chemical formula of the given compound by simply counting the number of carbon atoms and the compound it can form with oxygen and hydrogen. So the given compound can form an aldehyde and a ketone as:
$C{H_3} - C{H_2} - C{H_2} - C{H_2} - HC = O$
 or it can form a ketone as:
 $C{H_3} - C{H_2} - C{H_2} - CO - C{H_3}$

In the aldehyde compound, it contains four carbons and one aldehydic group in the ketone also, there are four five carbon with the ketonic group on one carbon.
It cannot have five or six carbons and then an aldehyde or four carbons and then a ketone. That is why the other options are incorrect.

Therefore the correct answer is (C).

Note: Ketones are of great importance in chemical industries as well as biology. They are produced as a solvent, polymer precursors and various pharmaceuticals. Most common are acetone and cyclohexanone. Many sugars involve ketones like fructose. The fatty acid synthesis takes place through ketones. Krebs cycle involves acetoacetate as an intermediate which is a ketone.