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You seem to be using a very simplified version of the index of hydrogen deficiency. A more complete expression is: I H D = 2 C + 2 − H − X + N 2 Where C, H, X, and N represent the number of carbon, hydrogen, halogen, and nitrogen atoms, respectively.
How does the index of hydrogen deficiency work?
Here is a summary of how the index of hydrogen deficiency (IHD) works. A double bond and ring each counts as one IHD. A triple bond counts as two IHD. (where x and y stand for # of C and H respectively.)
How do you know if there is hydrogen deficiency?
If any of the bonds are replaced with double or triple bonds, or if rings are involved, there would be a “deficiency” of H atoms. By calculating the index of hydrogen deficiency (IHD), we can tell from the molecular formula whether and how many multiple bonds and rings are involved.
How do you calculate HDI of an alkane?
HDI = ½ (2C + 2 + N – H – X) The formula for an alkane is C_nH_ (2n+2). For a cycloalkane or an alkene, the formula is C_nH_2n. Each time you insert a double bond or a ring, you lose two H atoms. So, a double bond or ring (HDI = 1) means a deficiency of 2 H atoms. That's where the factor of ½ in the formula comes from.
How do you find the IHD of a hydrocarbon?
A double bond and ring each counts as one IHD. A triple bond counts as two IHD. Hydrocarbons ( C x H y ): (1) I H D = 2 x + 2 − y 2. (where x and y stand for # of C and H respectively.) Example 1. IHD for C 2 H 4 is. (2) 2 ( 2) + 2 − 4 2 = 1.
What does HDI mean in math?
Each time you insert a double bond or a ring, you lose two H atoms. So, a double bond or ring (HDI = 1) means a deficiency of 2 H atoms. That's where the factor of ½ in the formula comes from. 2C+2 is the number of hydrogen atoms in the saturated alkane.
Does 3-hexyne work?
Yes, it still works. Think of 3-hexy ne. Molecular formula is C6H10.
Does oxygen affect IHD?
No the IHD would remain the same you would still have 6 carbons and 6 hydrogens, an oxygen atom has no effect on the IHD. The IHD is 4 and you would still have 2 double bonds inside the ring counting for 2. The one double bond on the carbonyl counting for another 1 making that a total of 3, plus the ring itself equals 4.
What is the formula for alkanes?
The general formula of alkanes (CnH2n+2) is used as the standard for determining and comparing different degrees of unsaturation as alkanes are saturated and the simplest in composition among organic molecules.
How does nitrogen affect HDI?
Comparing the structures of the following alkane and the amine, we can see that nitrogen is changing the number of expected hydrogen atoms. The nitrogen brought an extra H and it is now 9 instead of 8 hydrogens for three carbons.
How to calculate the degree of unsaturation?
In many cases, it is quite straightforward to determine the degree of unsaturation based on the number of multiple bonds and rings present in the molecule:
How many hydrogens are in C4H9Br?
For example, for the formula C4H9Br the expected number of hydrogens is 10 ( C4H10, an alkane with CnH2n+2 general formula). The number of hydrogen atoms is, however, 9 for 4 carbons even though there is no unsaturation occurring because of the bromine.
What is the degree of unsaturation of a molecule?
The molecule is saturated with what? The degree of unsaturation or HDI is the capacity of the molecule to connect more hydrogen atoms. The capacity is reached when the molecule has the maximum possible number of hydrogen atoms per carbon (and other atoms).
How many hydrogens are needed to make propane?
In total, it takes two hydrogens to get from propyne (an alkyne) to propane (an alkane) and because of this, the alkynes (with a single triple bond) are classified as hydrocarbons with two degrees of unsaturation. The alkenes with a single double bond have one degree of unsaturation.
How many degrees of unsaturation does a double bond have?
So every double bond brings one degree of unsaturation and every triple bond brings two degrees of unsaturation. It is worth to mention that this is not related to carbon atoms only. An oxygen with a double bond brings one degree of unsaturation, a nitrogen with a triple bond brings two degrees of unsaturation and etc.
Saturated and Unsaturated Compounds
Degrees of Unsaturation
Rings and Degrees of Unsaturation
How to Calculate The Degree of unsaturation?
The Effect of Halogens on Hdi
The Effect of The Oxygen on Hdi
The Effect of The Nitrogen on Hdi
Calculating Hdi by Using A Formula
- You can also calculate the HDI by using the following formula: For the previous example it would be: 1/2 (2×6 + 2 + 1 – 10 -1) = 2 Check this 60-question, Multiple-Choice Quiz with a 2-hour Video Solution coveringLewis Structures, Resonance structures, Localized and Delocalized Lone Pairs, Bond-line structures, Functional Groups, Formal Charges, Cu...