this is the second part of the acid-base extraction the isolation so i have placed the sodium hydroxide extract in an ice bath as well as the hcl extract in the ice bath so it will be cooled down before we go further i will first take the sodium hydroxide extract for the neutralization for the neutralization i would add hcl 6mhcl i would add hcl dropwise with the pipette until solid formation you should mix the solution once in a while i have added about seven milliliters of my hcl so now i'm gonna test the ph of the solution before i go further you can see there's a small bit of cloudiness on the extract it's still not acidic it's weakly acidic we would like to have it the strong acidic color so [Music] we will keep adding hcl now that i have added entire hcl solution so i will check the ph again to see whether it's acidic so it's strongly acidic that means the entire solution is uh the sodium hydroxide in the entire solution is completely reacted with the hcl so the benzoic acid is protonated again from the hcl and you can see there's a solid there so similarly i'm going to treat the hcl extract with one 6m sodium hydroxide first i'm going to pour out seven milliliters of sodium hydroxide like i did in the previous experiment now that i have added seven milliliters sodium hydroxide to the hcl extract i'm going to check the ph it's still acidic that means we need to add more sodium now i have added a few milliliters of sodium hydroxide again to the fgl extract we'll check the ph again so it's strongly basic that means the acid has completely neutralized in sodium hydroxide extract sodium benzoate is reacted with strong acid hcl which results in weak acid benzoic acid and sodium chloride benzoic acid precipitates in this reaction so sodium benzoate is water soluble because it has ionic properties which result in polar rarity so polar compound dissolve in polar solvents so it dissolves in water benzoic acid does not have polarity it has more non-polar property because of that it dissolves in organic compounds rather than water because of that it precipitates in the hcl extract we have the ammonium salt of paraniteranally so it is reacted with the strong base sodium hydroxide which results in weak base para nitro aniline and two other by-products sodium chloride and water so here ammonium chloride salt of the wheat base paranitro anneli is soluble in water because it has ionic properties likewise in the previous example polar compound dissolved in polar solvent so it dissolves in water but when the hydrogen is replaced and reacted with the oh group of the sodium hydroxide it becomes relatively nonpolar result in precipitation and now we will go to our organic extract which contains the only naphthalene so first we need to add drying agent to this organic extract because in the atheil acetate solution there can be some trapped water molecules when we need to remove all the water molecules from this organic layer so because of that we'll add a drying agent drying agent is magnesium sulfate anhydrous magnesium sulfate [Music] we'll add small amounts of magnesium sulfate until you don't see any clumping now we have added our drying agent so now our organic compound is dry enough we need to filter this organic layer because we need to remove the magnesium sulphate in the mixture so we'll be needing a folded filter paper and then we need to wet it with some ethyl acetate before we do the gravity filtration of our organic [Music] extract so the remaining will be washed with ethyl state so [Music] couple of washings will do fine so now our organic layer is filtered from the magnesium sulfate using gravity filtration so now we need to transfer this solvent into a round bottom flask so that we can remove the solvent and get the naphthalene back so and we'll wash the flask with a bit of ethyl acetate so there won't be anything trapped inside [Music] now we are going to filter our sodium hydroxide extract which contain benzoic acid we have set up our vacuum filtration setup here so we need cold water to wash up the remaining after filtering the benzoic extract i have to wet the filter paper in the harsh farmer with some cold water while mixing i'll add the sodium hydroxide extract to the vacuum file to filter the compound i'm gonna add some little bit of cold water to wash the flask and the crystals on the filter i have obtained the benzoic acid from the swana and i have measured the weight of this benzoic acid so now i need to transfer it to another flask now i have taken all the benzoic acid into the flask so i will now pour out small portions of hot water into this benzoic acid solid and then always try to use a minimum amount of water then i would place it in the hot plate [Music] if you use excess amount of water sometimes there won't be any crystal formation when you do the recrystallization so it's important to always use as small portions of water as much as you can while we are waiting for our solids to dissolve we need to heat our funnel as well as the flask that we are going to put our salt filtered into so though those two glasswares need to be heated before doing the filtration [Music] and i'm going to put a cotton small cotton plug into the fanner because we will not be using a filter paper to filter out the hot benzoic acid solution [Music] [Music] and i'll keep it back again hot plate so now our solution is ready to be filtered out it's it's important to know that you it takes more time to dissolve your benzoic acid in water it doesn't easily dissolve in water even though if it's boiling hot water you need to keep it a little bit more to have it completely dissolve so now we need to pour this solution quickly down this funnel while keep it in the hot plate so i'm going to wash my flask with some hot water and using that same hot water i'm going to rinse the flask funnel which has some solid foam on it so and now we are done with the filtration we are going to keep it until it goes to the room temperature and then we'll put it inside an ice path i have placed the benzoic acid solution in ice after it cooling down to room temperature it's important to keep it in ice for some time so you can have better crystal formation after this we will be doing the suction filtration to filter out the benzoic acid