Give the name for the product from the hydrogenation of each o...

Question

Give the name for the product from the hydrogenation of each of the following:

a. 3-methyl-2-pentene

Accepted Answer

All right. Hello everyone. So this question is asking us what is the correct name for the product of the hydrogenation of 35 dimethyl two hexane. Option A says 24 dimethyl hexane. Option B says 35 dimethyl hexane. Option C says 24 dimethyl, two hexen and option D says 35 dimethyl, three hexed. So before discussing the reaction that we have on hand, I want to go ahead and actually start by drawing out our starting material 35 dimethyl to hex starting off with the parent chain of two hexi. Now recall that the prefix X or hex indicates that there is a six carbon parent chain in this molecule. So thats the first thing I would drop. Now, the combination of the suffix E and E as well as the number two indicates that there is a double bond in between carbons, two and three of the parent chain. So thats too Hexing. Now let's go ahead and address our substituents. The phrase 35 dimethyl indicates that I have two methyl groups or one carbon substituent present in this molecule. One of them is attached to carbon three of the chain and the other is attached to carbon five. So that's 35 dimethyl two hexen. So now lets go ahead and talk about the reaction on hand here. The reaction on hand is the hydrogenation of an alkene. Specifically recall the hydrogenation of an all keen involves reacting in a keen with hydrogen gas in the presence of some metal catalyst. Common ones include platinum, nickel or pal but definitely a metal catalyst is required to make this reaction proceed faster. So the hydrogenation of an alkene involves the addition of hydrogen gas across both carbons of the starting alkene. So what that means is that each carbon of the starting double bond receives one additional hydrogen atom. And that in the process gets rid of the double bond in between them, producing an all cane as your final product. So in this case, the carbon backbone of the starting material is not going to change, we're going to have the same parent chain and the same substituents in the same position. The only difference is that now instead of having a double bond in between carbons two and three, you will simply have a single bond. So for my product, I will go ahead and start by drawing out my six carbon per and chain this time with no double wand in between carbons two and three, but I still have methyl groups on carbons three and five. Well, not necessarily carbon three and five anymore. And lets talk about why that is? Because now lets talk about the Iupac name of our final product starting off with the direction in which the carbon chain is numbered. Recall that if you don't have a situation like in the case of 35 dimethyl, two heene, or there's a double bond to take priority. When numbering a carbon chain, you have to make sure that substituents have the smallest number possible. And because I have one substituent closer to the right side than to the left, I would go ahead and start by numbering my parent chain going from right to left. Notice how that has changed the position numbers in which my methyl groups are, but there is still a six carbon parent chain this time with no double bond. So the name would simply be Hexane. But with respect to my substituents, recall that multiple of the same substituent would require some kind of prefix beforehand to specify how many there are these include die try tetra etc. So because there are two of the same substituent, the prefix dye would be appropriate. So that's dimethyl because I've got two methyl groups in this molecule. So this time according to the numbering of the parrot chain, to make sure that these methyl groups have the smallest number possible. This time they are on carbons two and four. So before the name dimethyl, I would write their respective position numbers with a comma in between them. So that's 2, 4 dash, dimethyl hexane using commas to separate numbers and dashes to separate numbers from letters. This means that my answer is going to be option a in the multiple choice because the hydrogenation product of 35 dimethyl, two hexane is 24 dimethyl hexane and there you have it. So with that being said, thank you so very much for watching and I hope you found this helpful.

Give the name for the product from the hydrogenation of each of the following:
a. 3-methyl-2-pentene

Key Concepts

Hydrogenation

Alkenes

Product Identification

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