Question
Question: The double bond equivalent of \({C_4}{H_6}\) is: A. \(0\) B. \(1\) C. \(2\) D. \(3\)...
The double bond equivalent of C4H6 is:
A. 0
B. 1
C. 2
D. 3
Solution
:Hint: Double bond equivalent is the level of unsaturation present in an organic compound. Unsaturation is defined as the presence of double bond or triple bond in the organic molecule. Ring is also considered in unsaturation. It is represented as DBE.
Formula used:
DBE=C+1−2H−2X+2N
Where,
C = Number of carbon atoms present in organic molecules.
H = Number of hydrogen atoms present in organic molecules.
X = Number of halogen atoms present in organic molecules.
N = Number of nitrogen atoms present in organic molecules.
Complete step by step answer:
As in simple words, the double bond equivalent is the number of double bonds and number of triple bonds present in organic molecules. For example, in the case of benzene, there are three double bonds and one ring so its double bond equivalent is four.
Similarly in the case of C4H6 ,
The molecular structure of C4H6 is CH2=CH−CH=CH2
As it is clearly seen that there are two double bonds present in C4H6 , so its level of unsaturation is two hence, its double bond equivalent is two.
Now, by the formula:
Here, in C4H6 there are four numbers of carbon atoms, and six numbers of hydrogen atoms.
By substituting the value in formula:
DBE=C+1−2H−2X+2N
Where,
C = Number of carbon atoms present in organic molecules.
H = Number of hydrogen atoms present in organic molecules.
X = Number of halogen atoms present in organic molecules.
N = Number of nitrogen atoms present in organic molecules.
We will get:
⇒DBE=4+1−26−0+0 ⇒DBE=5−3 ⇒DBE=2
So, the double bond equivalent of C4H6 is 2 .
Hence, option C is correct.
Note:
A triple bond can be regarded as DBE=2 . It must be noted that X is the total number of halogens, namely chlorine, fluorine and iodine present in the structure. Presence of an oxygen atom does not affect the double bond equivalent calculation.