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Salt metathesis is often employed to obtain salts that are soluble in organic solvents. Illustrative is the conversion of sodium perrhenate to the tetrabutylammonium salt: [2] NaReO 4 + N(C 4 H 9) 4 Cl → N(C 4 H 9) 4 [ReO 4] + NaCl. The tetrabutylammonium salt precipitates from the aqueous solution. It is soluble in dichloromethane.
Liposomes that contain low (or high) pH can be constructed such that dissolved aqueous drugs will be charged in solution (i.e., the pH is outside the drug's pI range). As the pH naturally neutralizes within the liposome ( protons can pass through some membranes), the drug will also be neutralized, allowing it to freely pass through a membrane.
The nucleophilic lysine residue is commonly targeted site in protein bioconjugation, typically through amine-reactive N-hydroxysuccinimidyl (NHS) esters. [3] To obtain optimal number of deprotonated lysine residues, the pH of the aqueous solution must be below the pKa of the lysine ammonium group, which is around 10.5, so the typical pH of the reaction is about 8 and 9.
An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula . For example, a solution of table salt , also known as sodium chloride (NaCl), in water would be represented as Na + (aq) + Cl − (aq) .
The salt metathesis reaction results in precipitation of solid calcium carbonate, leaving potassium hydroxide in solution: Ca(OH) 2 + K 2 CO 3 → CaCO 3 + 2 KOH. Filtering off the precipitated calcium carbonate and boiling down the solution gives potassium hydroxide ("calcinated or caustic potash").
Acetic acid (CH 3 COOH) and ammonium (NH + 4) are good examples. Acetic acid is extremely soluble in water, but most of the compound dissolves into molecules, rendering it a weak electrolyte. Weak bases and weak acids are generally weak electrolytes. In an aqueous solution there will be some CH 3 COOH and some CH 3 COO − and H +.
Berberine, a plant compound traditionally used in herbal medicine, is today commonly stocked on the shelves of health food stores and pharmacies as a supplement. Beyond weight loss, berberine also ...
In an aqueous system, the polar heads of lipids align towards the polar, aqueous environment, while the hydrophobic tails minimize their contact with water and tend to cluster together, forming a vesicle; depending on the concentration of the lipid, this biophysical interaction may result in the formation of micelles, liposomes, or lipid bilayers.