Which functional group is least polar?

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Accepted Answer

Welcome back, everyone. We need to list the following organic compounds. In order of decreasing polarity, we have C H three H two H which we should recognize as the condensed formula for ethanol. We have 33, which we should recognize as the condensed formula for dimethyl ether. Our third compound is C H three coo H which we should recognize as the condensed formula for acetic acid. The fourth compound is C two H six, which we should recognize as the condensed formula for ethane. And our fifth compound is C H three C O H which we should recognize as the condensed formula for ace aldehyde. So that's ac eta L D E H Y D. So a seed al to hide now with our compounds listed out, we're going to recall some facts. First, beginning with the fact that we would observe increasing polarity for any of our organic compounds along with an increase in the number of electron negative, or we'll say the number of polar atoms which are highly electron negative within functional groups in our compounds. So we're going to next recall that the most polar atoms on our periodic table include oxygen nitrogen and then the most electron negative atom or most polar atom fluorine. Let's also recall that more polar atoms can be considered our halogens in group seven A on the periodic table. And these atoms all correspond to our increasing trend for electron negativity which increases towards the top right of the periodic table. So now we're going to analyze the structures of each of our compounds. Beginning with ethanol, we're going to have our ethyl group C H three C H two, which is then bonded to a hydroxyl group where we have a bond to oxygen which is bonded to hydrogen. So recognize that the presence of this hydroxyl group creates a dipole from the direction of hydrogen towards oxygen in the oxygen hydrogen bond, as well as from the direction of carbon towards oxygen in the carbon oxygen bond. And we also have an asymmetrical structure. So these dipoles will not cancel. So overall, we can list ethanol as a polar structure because it contains our hydroxyl group which is polar due to the presence of oxygen. Now, we have our second structure to analyze dimethyl ether. Recall that for dimethyl ether, we have an ether group characterized by an oxygen surrounded by two alkyl chains where in this case, our two alkyl chains are methyl groups. So we're going to observe that we have dipoles again, going towards oxygen from each carbon oxygen bond. And due to the fact that we have symmetry, because we have two methyl groups, we have a symmetrical structure. So the diapers cancel and dimethyl ether, we can list as non polar. So, so far ethanol has a higher polarity than dimethyl ether. We can list ethanol as ranked by number one with the highest polarity. Now, let's analyze our structure for acetic acid. So for acetic acid, we have a methyl group which is bonded to a carbonyl group where we have carbon double bonded to an oxygen atom. And that Carboni is then bonded to a hydroxyl group. So not only do we have a dipole going towards the oxygen in our Carboni, but we also have a dipole going towards oxygen in our hydroxyl group, we also have an asymmetrical structure. So the dipoles will not cancel. And thus, because we have two functional groups, we'll say two polar functional groups and acetic acid, we can now rank acetic acid as number one being the most polar. And we can rank ethanol as number two, which is less polar than acetic acid because it only has one polar hydroxyl group. So now moving on to our next structure to analyze we have ethane. So we'll draw ethane where we have a two carbon chain where at each carbon, we have three implied bonds to hydrogen which we will draw in just for clarity. So let's recall that within ethane, we have carbon hydrogen bonds and then a carbon carbon bond, the election activity values for carbon and hydrogen are very low and thus, carbon, hydrogen, carbon, carbon bonds are minimally polar. They have a low polarity. We also have symmetry since we have two C H three groups in the structure of ethane. And thus, because of this, we can say overall, we have a nonpolar structure for ethane. Now, between dimethyl ether and ethane, at least dimethyl ether had the presence of oxygen although its dipoles canceled out. So we would list dimethyl ether as ranked number three for polarity and ethane as number four, which has a lower polarity than dimethyl ether. Now let's analyze our last structure ace aldehyde. So for acid aldehyde, we have ach three or methyl group which is bonded to a carbonyl or carbon double bonded to an oxygen where that carbonyl carbon is then bonded to a hydrogen atom. So let's recognize that we have a dipole going towards the oxygen in our carbon eal. And we also have, technically, although the election activity value for carbon is small, we technically have a dipole going towards the direction of carbon in our carbon hydrogen bond. Thus, overall, we have a polar structure for acid aldehyde. And since it contained the carbonyl polar functional group, we have a polar structure. Overall, the net dipoles do not cancel. And thus, we will now change our third ranked most polar compound to a seed aldehyde as number three. And that would make dimethyl ether ranked number four. Now with Ethane ranked as number five being the least polar. So writing out our ranking fully, in order of decreasing polarity, we would begin with acetic acid, which we stated is ranked as number one C H three coo H which had the greatest polarity, an even greater polarity than what we ranked as number two for ethanol, which was C H three C H2O H ethanol had an even greater polarity and let's make some room. So ethanol had an even greater polarity than what we ranked as number three, which was ace aldehyde C H three C O H. Then we ranked as number four dimethyl ether, which had a lower polarity than ace aldehyde. So dimethyl ether was C H 30 C H three and then our lowest or least polar compound, we ranked as Ethane C two H six. And so our final answer is going to be the decreasing polarity order that we have determined in which acetic acid, which contained two polar functional groups being our carbonyl and hydroxyl functional groups was the most polar compound. And Ethane, which contained only carbon, hydrogen and carbon carbon bonds with low polarity was a nonpolar structure and thus the least polar out of all of our structures. So this entire ranking is our final answer. I hope this made sense. And let us know if you have any questions.

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Which functional group is least polar?

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