so in this video i am going to demonstrate the color changes involved with titrations and how that is dependent on which solution we start with in our conical flask and which we start with in our burette you'll see that the chemicals i'm using here are hydrochloric acid as my acid and sodium hydroxide as my base or my alkali the two indicators i'm going to demonstrate are phenolphthalein which you perhaps met with gcse and methylarns which you maybe haven't met before and you'll see here i have measured out 25 mils of my acid and my base into a conical flask and i've got two sets of these to demonstrate the two indicators so what i'll start off by doing is perhaps my acid in the conical flask and to show the color change i will then add the base to that i will add sodium hydroxide from my buret so you can see here i've got my buret set up and on the left hand side i have it filled with hydrochloric acid and on the right hand side i have it filled with the sodium hydroxide the base and so for each of the colour change demonstrations i will be adding the opposite solution to the conical flask so i'm going to start by having sodium hydroxide in my conical flask and so i've rotated the burette clamp so that the buret containing acid is over the conical flask so i'm adding acid hydrochloric acid to my base sodium hydroxide and i'm going to start with the indicator of phenolphthalein so i'm going to start by adding just a few drops into my conical flask indicator is always added to the conical flask so your starting color is essentially what color is that indicator in the solution that is in the conical flask so think about it we have sodium hydroxide which is a base or an alkali in our conical flask phenolphthalein is pink and alkali and so therefore my starting color is pink so let's see what happens when we add our acid so i will um turn the tab so that the acid is not adding to the base now i'm not doing this as an accurate titration i don't want to necessarily measure the volume that it requires to neutralize my base but you can see um all we're demonstrating here is the color change and you can see the color change that has happened here is that the pink color has disappeared and it has turned colorless so the color change when we start with base in our conical flask and add acid to it with the use of phenolphthalein indicator the colour change is pink to colorless but what about if we do it the other way round if i was to swap this for an acid in my conical flask if i added a few drops of phenolphthalein indicator to my conical flask this time you can see that there's no color change my solution remains colourless so this time what i want to do is i want to add base to it so i'm going to rotate my buret clamp so that the base is over the conical flask so i'm now adding sodium hydroxide to the hydrochloric acid and let's see what the color changes now if you look closely you can probably see a bit of color there but when i swirl it that color disappears and i've just got a white tile at the bottom here and at the back of the retort stand just so that you can see that color change really well if i keep adding my base again i'm not too worried about being accurate here if i keep adding it until there's a constant color you can see that it has turned pink okay and that's because phenolphthalein is pink in alkali so we can see this time where we start with acid in the conical flask using phenolphthalein as my indicator and adding base from the buret the color change is colorless to pink okay so now i'm going to do the same process again but i'm going to use a different indicator this time i'm going to use the indicator of methyl orange which you may not have met before and you can see that the indicator to start with is a lovely orange color and hence the name and again i'm going to start with base in the conical flask as it is in your notes i'm going to put it under the burette here and this is my buret containing hydrochloric acid so if i add a few drops of the indicator to the conical flask remember the indicator um is always added to the conical flask if i add a few drops here it's maybe not as strong a color as with final filling and but hopefully you can see there and that we get a nice yellow color when methyl orange is added to your base so you can see the color in the conical flask the starting color as such um is yellow okay so what i'm going to do now is i'm going to add my acid again not too concerned um about the volumes here about it being precise you can see it's starting to change color there but um on swirling it's gone back to yellow and when it's all sufficiently mixed okay and now you can see the color change and has finished and what we end up with there and is kind of a pinky color there but it's referred to as red it's probably because we don't have too strong a concentration of our indicator if i add a couple of extra drops we'll see if we can see that color any more intensely and but the color change we refer to with methyl orange is yellow to red when we're going from a base in the conical flask and adding an acid from our buret let's try it now the other way around and this time starting with our acid in the conical flask and i'll move this burette rind before i do that i'm so moving it right now so that the base is being added to the conical flask from the buret okay so again i've got acid in my conical flask let's add a few drops of the indicator and you can have a think about what color you might expect and so as you may be expected from the opposite way rowing to the last demonstration our starting color this time is red okay so our starting color this time is red in the conical flask and let's see what happens when i open up my tap and add the base from the burette you can see it's starting to change color there okay and there's our color change complete so you can see that um as we add base from our burette to our conical flask containing acid the color change is red to yellow and that's with the use of the indicator methyl orange so when you're describing color change and for a titration just always think what's in the conical flask that's the color it starts in so methyl orange is yellow and in base and red in acid and so we started if you remember with and acid in this conical flask which started as red because we had acid in the conical flask and then it turned to yellow because we have bs in the buret so you're almost thinking what's the color change conical flask to buret acid to base in this case