Sodium ethanoate

\( \newcommand\) • • • • • This page describes the reaction between alcohols and metallic sodium,and introduces the properties of the alkoxide that is formed. We will look at the reaction between sodium and ethanol as being typical, but you could substitute any other alcohol and the reaction would be the same. The Reaction between Sodium Metal and Ethanol If a small piece of sodium is dropped into ethanol, it reacts steadily to give off bubbles of hydrogen gas and leaves a colorless solution of sodium ethoxide: \(CH_3CH_2ONa\). The anion component is an alkoxide. \[2CH_3CH_2OH_\] If the solution is evaporated carefully to dryness, then the sodium hydroxide (\(NaOH\)) is left behind as a white solid. We normally, of course, write the sodium hydroxide formed as \(NaOH\) rather than \(HONa\) - but that's the only difference. Sodium ethoxide is just like sodium hydroxide, except that the hydrogen has been replaced by an ethyl group. Sodium hydroxide contains \(OH^-\) ions; sodium ethoxide contains \(CH_3CH_2O^-\) ions. Note The reason that the ethoxide formula is written with the oxygen on the right unlike the hydroxide ion is simply a matter of clarity. If you write it the other way around, it doesn't immediately look as if it comes from ethanol. You will find the same thing happens when you write formulae for organic salts like sodium ethanoate, for example. There are two simple uses for this reaction: • To safely dispose of small amounts of sodium: If you spill some sodium ...

• • • • Syllabus ref: 18.1 Buffer solutions may be made directly by mixing weak acids/bases with their salts or by reaction between weak acids/bases and strong base/acid to produce the required mixture. • • • Preparation of an acidic buffer The simplest way of preparing a buffer solution is to dissolve a known quantity of the salt of the weak acid (or base) in a solution of weak acid (or base) of known concentration. Example Sodium ethanoate is the salt of a weak acid - it has the formula CH 3COONa (relative molecular mass = 82) If 8.2 g of sodium ethanoate are dissolved in 100 cm 3 of ethanoic acid then: The concentration of the sodium ethanoate is equal to 0.1/0.1 = 1M The concentration of the ethanoic acid = 1M Therefore the buffer solution will have pKa = pH Therefore the buffer has a pH value of 4.78 top Preparation of a basic buffer A basic buffer is prepared using a weak base and its salt. The classic example is ammonia solution and ammonium chloride. • Ammonia solution is the weak base - NH 3(aq) • Ammonium chloride is the salt of ammonia - NH 4Cl(aq) The pOH of the solution may be calculated using the pkb value of ammonia (4.75), or the Kb of ammonia (1.78 x 10 -5). Once the pOH is found, the pH is calculated using the relationship pH + pOH = 14. Example: Calculate the pH of a buffer solution consisting of a 0.2 mol dm -3 solution of ammonium chloride in 0.1 mol dm -3 ammonia solution (pKb = 4.75). The base equilibrium expression: Separate out the [OH-] Take logs ...

Sodium Acetate Generic name: Sodium Acetate [ SOW-dee-um-AS-e-tate] Drug classes: • • • • • • Uses of Sodium Acetate: • It is used to treat low sodium levels. • It is used in the diet to meet sodium needs. • It may be given to you for other reasons. Talk with the doctor. What do I need to tell my doctor BEFORE I take Sodium Acetate? • If you have an allergy to sodium acetate or any other part of sodium acetate. • If you are allergic to sodium acetate; any part of sodium acetate; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had. • If you have high sodium levels or swelling. This is not a list of all drugs or health problems that interact with sodium acetate. Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, What are some things I need to know or do while I take Sodium Acetate? • Tell all of your health care providers that you take sodium acetate. This includes your doctors, nurses, pharmacists, and dentists. • Have blood work checked as you have been told by the doctor. Talk with the doctor. • This medicine may contain aluminum. There is a chance of • Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using sodium acetate while you are pregnant. • Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby. Related/similar drugs How is this medicine (Sodium Acetate) best taken...

\( \newcommand\) • • • • • • • • This page looks at the simple reactions of carboxylic acids as acids, including their reactions with metals, metal hydroxides, carbonates and hydrogencarbonates, ammonia and amines. The acidity of the carboxylic acids Using the definition of an acid as a "substance which donates protons (hydrogen ions) to other things", the carboxylic acids are acidic because of the hydrogen in the -COOH group. In solution in water, a hydrogen ion is transferred from the -COOH group to a water molecule. For example, with ethanoic acid, you get an ethanoate ion formed together with a hydroxonium ion, H 3O +. This reaction is reversible and, in the case of ethanoic acid, no more than about 1% of the acid has reacted to form ions at any one time. (This is a rough-and-ready figure and varies with the concentration of the solution.) These are therefore weak acids. \[ CH_3COOH + H_2O \rightleftharpoons CH_3COO^- + H_3O^+\] This equation is often simplified by removing the water to: \[ CH_3COOH (aq) \rightleftharpoons CH_3COO^- (aq) + H^+\] However, if you are going to use this second equation, you must include state symbols. They imply that the hydrogen ion is actually attached to a water molecule. The pH of carboxylic acid solutions The pH depends on both the concentration of the acid and how easily it loses hydrogen ions from the -COOH group. Ethanoic acid is typical of the acids where the -COOH group is attached to a simple alkyl group. Typical lab solutions h...

\( \newcommand\) • • • • • This page describes ways of making esters in the lab from alcohols and phenols using carboxylic acids, acyl chlorides (acid chlorides) or acid anhydrides as appropriate. Making esters from carboxylic acids This method can be used for converting alcohols into esters, but it doesn't work with phenols - compounds where the -OH group is attached directly to a benzene ring. Phenols react with carboxylic acids so slowly that the reaction is unusable for preparation purposes. Esters are produced when carboxylic acids are heated with alcohols in the presence of an acid catalyst. The catalyst is usually concentrated sulphuric acid. Dry hydrogen chloride gas is used in some cases, but these tend to involve aromatic esters (ones where the carboxylic acid contains a benzene ring). If you are a UK A level student you won't have to worry about these. The esterification reaction is both slow and reversible. The equation for the reaction between an acid RCOOH and an alcohol R'OH (where R and R' can be the same or different) is: So, for example, if you were making ethyl ethanoate from ethanoic acid and ethanol, the equation would be: Doing the reactions On a test tube scale: Carboxylic acids and alcohols are often warmed together in the presence of a few drops of concentrated sulfuric acid to observe the smell of the esters formed. You would normally use small quantities of everything heated in a test tube stood in a hot water bath for a couple of minutes. Becaus...

\( \newcommand\) • • • • • • • • Esters hydrolysis Esters are neutral compounds, unlike the acids from which they are formed. In typical reactions, the alkoxy (OR′) group of an ester is replaced by another group. One such reaction is hydrolysis, literally “splitting with water.” The hydrolysis of esters is catalyzed by either an acid or a base. Acidic hydrolysis is simply the reverse of Example \(\PageIndex\) Write an equation for the acidic hydrolysis of ethyl butyrate (CH 3CH 2CH 2COOCH 2CH 3) and name the products. Solution Remember that in acidic hydrolysis, water (HOH) splits the ester bond. The H of HOH joins to the oxygen atom in the OR part of the original ester, and the OH of HOH joins to the carbonyl carbon atom: Basic Hydrolysis or saponification When a base (such as sodium hydroxide [NaOH] or potassium hydroxide [KOH]) is used to hydrolyze an ester, the products are a carboxylate salt and an alcohol. Because soaps are prepared by the alkaline hydrolysis of fats and oils, alkaline hydrolysis of esters is called saponification (Latin sapon, meaning “soap,” and facere, meaning “to make”). In a saponification reaction, the base is a reactant, not simply a catalyst. The reaction goes to completion: Example \(\PageIndex\) Write an equation for the hydrolysis of methyl benzoate in a potassium hydroxide solution. Solution In basic hydrolysis, the molecule of the base splits the ester linkage. The acid portion of the ester ends up as the salt of the acid (in this case, ...