in this video, we're going to begin our discussion on reducing sugars tests. So it turns out that there are actually several different experimental tests that can detect the presence of reducing sugars. And one of these tests is the failings tests for reducing sugars and so failings Test is named after the scientist who helped develop it. And so failings test is really just an experimental color change reaction and as well see the color is going to change from a blue color to a reddish color in the presence of a reducing sugar. And so, really, this color change reaction is just again testing for the presence of reducing sugars. And so we'll see that this failings test uses a blue Kubrick ion solution as the oxidizing agent. And so, in the presence of a non reducing sugar, the Blue Kubrick ion is not going to be reduced. And so that means that the Blue Cooper Kayan is going to remain it's blue color and the presence of non reducing sugars. However, when the blue Kubrick ion is in the presence of reducing sugars, then the blue Kubrick ion will be reduced and it will ultimately generate this red Kubrick oxide precipitate. And so what you'll notice is that the blue solution and the presence of over reducing sugar will change from a blue color to a red color. So when the color changes to a red color that indicates the presence of a reducing sugar. So let's take a look down below at our image and notice up here at the top left, we have a cyclic sugar that is actually a reducing sugar, and we can tell that it's reducing because when we look at the end, um, Eric Carbon right here notice that it's present forming a Hemi a settle. And so, of course, heavy ass settles we know are going to be relatively unstable. And so they're unstable where they can actually, uh, react to generate its linear form again. So here we have the linear form of the same cyclic sugar and notice that it has a free Aldo Hide group that's capable of being oxidized. And so notice that in the presence of the Kubrick ion oxidizing agent, the alga hide group is being oxidized here so you can see that it's turning into a car box cilic acid and notice that in the process. The Kubrick ion molecule here is being reduced in its charge, and ultimately, the reduced Kubrick ion can react to form a Kubrick oxide precipitate that is going to be a red color. And so the idea here is that when there are no reducing sugars, the Cooper ion solution is going to remain blue. And so this is going to be our negative control with no reducing sugars present. And no reducing sugars means that no precipitate is going to form, however, in the presence of a reducing sugar. Of course, this Kubrick ion oxide precipitate is going to form, so we will get a red color, which is our positive control in the presence of reducing sugars. And so we will get a red Kubrick oxide precipitate in the presence of reducing sugars. And so, really, the main summary of the failings test is that if the solution does turn this reddish brownish brick color over here, then that indicates the presence of a reducing sugar. And if it does not turn this reddish brownish color over here and it remains blue, then that means that there are no reducing sugars present, and any sugars that are present would be non reducing. And so, really, it's just a simple color change reaction. And in our next video, we'll be able to talk about another test for reducing sugars called the Benedicts Test, which is very similar to the failing steps. So I'll see you guys in our next video.
Reducing Sugar Tests
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Now your professors and your textbooks may also mention another test for reducing sugars called the Benedicts test. And so the Benedicts test is really just a very, very, very similar test to the failings test in terms of the overall reaction and the overall test result. And so the Benedicts test is a color change test, and so the change in color will indicate the presence of reducing sugars. Now, Benedict Solution, which is used in Benedict's test, is going to use slightly different re agents than the failings test. But again, overall, the reaction is very similar, and the test results are very similar. However, one thing to note about Benedicts solution is that, uh, it actually does have a longer shelf life than the failings test. And so in labs, you might find that the Benedicts test is mawr readily available because of its longer shelf life. But other than this longer shelf life, you can pretty much think of the failings test as pretty much being equivalent to the Benedicts test. And so again, they're gonna be very, very, very similar. And so that concludes our lesson on the Benedicts test and in our next lesson, video will be able to talk about the last test for reducing sugars that will cover, which is the Ta Lin's test for reducing sugar. So I'll see you guys in that video.
Reducing Sugar Tests
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all right, So the last test for reducing sugars that we're going to talk about is the Talyn's test. Now the Talyn's test will actually use silver or a G as the oxidizing agent. Instead of using Kubrick ion. Like the Failings and Benedicts tests used, however, talents test is still going to be testing for the presence of reducing sugars, just like failings and Benedicts test test for the presence of reducing sugars. And so, if we take a look down below at our image, notice that Failings and Benedicts test does use that blue Kubrick ion complex. And so in the presence of a reducing sugar like De Manos, which has a free alga hide group. We already know from our previous awesome videos that failings and Benedicts test eyes going to oxidize the reducing sugar here so that it is forming this car box Cilic acid this demon OIC acid here and in the presence of a reducing sugar like this one, the color is going to change from the blue Kubrick ion complex to the red brick, uh, cooper oxide precipitate. And so there is a color change and this red brick, uh, color change indicates the presence of of reducing sugar now with the Ta Lin's test that we're introducing now, which will notice, is that it uses Silver as the oxidizing agent instead of using the Blue Kubrick ion like failings and Benedicts test uses. And you can see that there are a variety of different solutions that could be used for talons test. But all of them include the silver and so in the presence of a reducing sugar like de manos. The talons test eyes also going to oxidize, uh, the reducing sugar so you can see that it's oxidized to this car box like acid here, and it's also going to create a color change. However, the color changes not gonna be a red brick precipitate. Instead, the color changes just going to be a silver mirror with the tones test, since it's using silver and so you can see over here we have a positive test, and you can see how, uh, it's really creating just a silver mere kind of color change. And over here we just have the clear solution. So this is what it would end up looking like, very clear. If there were no reducing sugars But if there is a reducing sugars, the color would change to the Silver Mirror. And so the talents test is still a color change test testing for the presence of reducing sugars. And so this year concludes our introduction to the talents test and, as we move forward, will be able to apply the concepts that we've learned, so I'll see you guys in our next video.
Which of the following would you predict to be the LEAST reactive in a Fehling's test for reducing sugars?
Which of these statements is false?
The Fehling’s test allows us to detect the presence of reducing sugars.
The Benedict’s test allows us to detect the presence of sugars with a free aldehyde or ketone group.
All simple, linear monosaccharides are reducing sugars.
All disaccharides have exposed carbonyl groups and are also reducing sugars.
Sucrose and other non-reducing sugars will not react with Tollens’ solution.
In the table below, indicate what the result of a Fehling’s, Benedict’s, and Tollen’s test would be for each of the two sugars and what conclusion can be made about the properties of the sugars.