Step 1The mixture solution was partitioned by pouring it into a separatory funnel containing 10 mL water, and the organic layer was extracted with 10 mL 1 M NaOH(aq).Step 2The aqueous layer was transferred to Flask A, and concentrated HCl(aq) was added dropwise to the flask until pH paper indicated that the solution was acidic.  Flask A was then placed in ice water to induce precipitate formation.Step 3The organic layer was extracted with 10 mL 3 M HCl(aq).  The resulting aqueous layer was then transferred to Flask B and 8 M NaOH was added dropwise to Flask B until pH paper indicated that the solution was basic.  Flask B was then placed in ice water, to maximize precipitate formation.Step 4The precipitates in flasks A and B were collected separately by vacuum filtration, rinsed with distilled water, and dried in an oven.Step 5The organic layer was transferred into Flask C and dried by adding anhydrous MgSO4 to remove any residual water present.  The organic solvent was separated from the MgSO4 in Flask C by gravity filtration, and the solvent was evaporated, yielding white crystals.Step 6The purity of the three isolated compounds was analyzed by thin-layer chromatography (TLC) on silica plates.  A sample of the mixture was spotted on the TLC plate as a reference in addition to the isolated compound. Question 41In which of the following steps is 2-naphthoic acid separated from the mixture?A.Step 1B.Step 3C.Step 4D.Step 5

A student separated a 2-g mixture of fluorene, 2-naphthoic acid, and diphenylamine (shown below) dissolved in 25 mL of the organic solvent diethyl ether.The separation experiment was performed according to the following steps:Step 1The mixture solution was partitioned by pouring it into a separatory funnel containing 10 mL water, and the organic layer was extracted with 10 mL 1 M NaOH(aq).Step 2The aqueous layer was transferred to Flask A, and concentrated HCl(aq) was added dropwise to the flask until pH paper indicated that the solution was acidic.  Flask A was then placed in ice water to induce precipitate formation.Step 3The organic layer was extracted with 10 mL 3 M HCl(aq).  The resulting aqueous layer was then transferred to Flask B and 8 M NaOH was added dropwise to Flask B until pH paper indicated that the solution was basic.  Flask B was then placed in ice water, to maximize precipitate formation.Step 4The precipitates in flasks A and B were collected separately by vacuum filtration, rinsed with distilled water, and dried in an oven.Step 5The organic layer was transferred into Flask C and dried by adding anhydrous MgSO4 to remove any residual water present.  The organic solvent was separated from the MgSO4 in Flask C by gravity filtration, and the solvent was evaporated, yielding white crystals.Step 6The purity of the three isolated compounds was analyzed by thin-layer chromatography (TLC) on silica plates.  A sample of the mixture was spotted on the TLC plate as a reference in addition to the isolated compound. Question 41In which of the following steps is 2-naphthoic acid separated from the mixture?A.Step 1B.Step 3C.Step 4D.Step 5

The pH of solution formed by mixing 40 mL of 0.10 M HCl and 10 mL of 0.45 M of NaOH is

30 ml of 0.1N HCI is added from burette into 20 ml of 0.11 N NaHCO3solutions in flask. Calculate pH of the titration mixture.

1. A burette was rinsed with deionised water but was not rinsed with the river water sample before filling it.Consequence: The river water would be because of residual water, and the concentration of hydronium ion in the river water and the pH .2. A  volumetric flask used to make the NaOH standard is filled past the mark.Consequence: The concentration of the NaOH standard would be than thought. A volume of river water would be needed to neutralise the standard. The concentration of acid in the river water would be .3. NaOH on the balance for a while before the mass is recorded. Consequence: NaOH is , meaning that it absorbs moisture from the air.  The amount of NaOH is therefore than thought.  The concentration of the NaOH standard would be than thought. A larger volume of river water would be needed to neutralise the standard. The concentration of acid in the river water would be .

A colorless aqueous solution contains nitrates of two metals, X and Y. When it was added to an aqueous solution of NaCl, a white precipitate was formed. This precipitate was found to be partly soluble in hot water to give a residue P and a solution Q. The residue P was soluble in aq. NH3 and also in excess sodium thiosulfate. The hot solution Q gave a yellow precipitate with KI. The metals X and Y, respectively, are4 pointsAg and PbAg and CdCd and PbCd and Zn