Sodium hydroxide dissolving

Sodium hydroxide. Dissolve a few crystals of benzoquinone in 10% aqueous NaOH solution and shake gently. The solution turns rapidly brown and then almost black owing to atmospheric oxidation. 

To obtain a maximum yield of the acid it is necessary to hydrolyse the by-product, iaoamyl iaovalerate this is most economically effected with methyl alcoholic sodium hydroxide. Place a mixture of 20 g. of sodium hydroxide pellets, 25 ml. of water and 225 ml. of methyl alcohol in a 500 ml. round-bottomed flask fitted with a reflux (double surface) condenser, warm until the sodium hydroxide dissolves, add the ester layer and reflux the mixture for a period of 15 minutes. Rearrange the flask for distillation (Fig. II, 13, 3) and distil off the methyl alcohol until the residue becomes pasty. Then add about 200 ml. of water and continue the distfllation until the temperature reaches 98-100°. Pour the residue in the flask, consisting of an aqueous solution of sodium iaovalerate, into a 600 ml. beaker and add sufficient water to dissolve any solid which separates. Add slowly, with stirring, a solution of 15 ml. of concentrated sulphuric acid in 50 ml. of water, and extract the hberated acid with 25 ml. of carbon tetrachloride. Combine this extract with extract (A), dry with a httle anhydrous magnesium or calcium sulphate, and distil off the carbon tetrachloride (Fig. II, 13, 4 150 ml. distiUing or Claisen flask), and then distil the residue. Collect the wovaleric acid 172-176°. The yield is 56 g. 

Benzenedisulfonic acid [831-59-4] (disodium salt), produced by the neutralization of the disulfonic acid with sodium sulfite [7757-83-7] is used in the manufacture of resorcinol [108-46-3] (1,3-benzenediol) (2), a chemical component found in mbber products and wood adhesives (72). The disodium salt is fused with sodium hydroxide, dissolved in water, and acidified to produce resorcinol, which is isolated via extraction (73). 

The commercial grade of flaked sodium hydroxide dissolves readily and is convenient to handle. Any silica present is not objectionable since it is removed by filtering the redissolved sodium salt before precipitating the product with acid. 

Dithioglycerol is prepared in the following manner 1,537 parts of sodium monosulfide nonahydrate and 411 parts of powdered sulfur are dissolved with stirring in 1,345 parts of water. Magnesium hydroxide is precipitated in the stirred sodium trisulfide solution by adding successively 97 parts of sodium hydroxide dissolved in 180 parts of water and then slowly 246 parts of magnesium chloride hexahydrate dissolved in 180 parts of water. The... 

A solution of 50 grams of N-(a-methylhomoveratryl)-3-methoxy-4-ethoxyphenylacetamide, prepared as set out above, in 200 cc of benzene, is treated with 8 cc of phosphorus oxychloride. The mixture is refluxed for about 3 hours, cooled and then is shaken with a solution composed of 15 grams of sodium hydroxide dissolved in 60 cc of water. The aqueous layer is removed, and the benzene solution is washed with water. The washed benzene solution is dried over anhydrous magnesium sulfate, filtered and evaporated to dryness. The low-melting solid residue is 6,7-dimethoxy-3-methyl-1-(3 -methoxy-4 -ethoxybenzyl)-dihydroisoquinoline base. 

To the chlorobenzene solution is then added sodium hydroxide dissolved in water and the chlorobenzene is removed by a steam distillation. After all of the chlorobenzene is removed, the precipitate which forms during the distillation is removed by filtration and discarded. The solution is cooled and acidified with hydrochloric acid, precipitating a tan solid. This is removed by filtration and washed acid-free. It Is then treated with sodium bicarbonate solution to remove any acid present and is then washed with water to remove all traces of bicarbonate. After drying approximately a 75% yield of mexenone is obtained. 

Some solutes have large heats of solution, and care should be taken in preparing solutions of these substances. The heat evolved when sodium hydroxide dissolves is 44.5 kj/mol. What is foe final temperature of foe water, originally at 20.0°C, used to prepare 1.25 L of 6.00 M NaOH solution Assume that all the heat is absorbed by 1.25 L of water, specific heat = 4.18 J/g °C. 

WEB Consider the process by which sodium hydroxide dissolves in water ... 

Immediately after the sodium hydroxide dissolves, the concentrations of H+fag) and... 

Procedure B (carbonate-free sodium hydroxide). Dissolve 50 g of sodium hydroxide in 50 mL of distilled water in a Pyrex flask, transfer to a 75 mL test-tube of Pyrex glass, and insert a well-fitting stopper covered with tin foil. Allow it to stand in a vertical position until the supernatant liquid is clear. For a 0.1 M sodium hydroxide solution carefully withdraw, using a pipette fitted with a filling device, 6.5 mL of the concentrated clear solution into a 1 L bottle or flask, and dilute quickly with 1 L of recently boiled-out water. 

FIGURE 14.17 A diaphragm cell tor the electrolytic production of sodium hydroxide from brine (aqueous sodium chloride solution), represented by the blue color. The diaphragm (gold color) prevents the chlorine produced at the titanium anodes from mixing with the hydrogen and the sodium hydroxide formed at the steel cathodes. The liquid (cell liquor) is drawn off and the water is partly evaporated. The unconverted sodium chloride crystallizes, leaving the sodium hydroxide dissolved in the cell liquor. 

In a 500-ml., three-necked, round-bottomed flask fitted with a mechanical stirrer and a thermometer is placed 42 g. (1.05 mole) of sodium hydroxide dissolved in 168 ml. of water. The contents of the flask are cooled to —20° and stirred vigorously as 48 g. (0.30 mole) of pyridinium-1-sulfonate (Note 1), which has been previously chilled to — 20°, is added in one portion. The mixture is stirred for 20 minutes while the temperature is kept below —5° (Note 2). The cooling bath is removed, and the mixture is stirred and warmed gradually to 20° over 20 minutes. The temperature of the dark orange mixture is then raised to 55-60° and after 1 hour is lowered again to —5°. The brown crystals that separate are filtered by suction, pressed into a compact filter cake, and washed with three 100-ml. portions of acetone (Note 3). The yield of this crude product amounts to 46-52 g. after drying on filter paper overnight or at 50° (1 mm.) for 1 hour. (Note 4). 

Read the label of the crystal drain cleaner package. Understand that the compound is solid sodium hydroxide that contains aluminum. When the material is added to water, sodium hydroxide dissolves rapidly, producing heat. Aluminum reacts with water in the basic solution to produce Al(OH)4 ions and hydrogen gas. Is aluminum oxidized or reduced in the reaction Is hydrogen oxidized or reduced in the reaction Explain your answers. 

The slurry from the ERH sump is pumped to one of two continuously stirred reactors (two for each ERH, four for the plant) to complete the hydrolysis, if necessary. Because the sodium hydroxide dissolves any aluminum present in the munitions, converting it to aluminum hydroxide, the aluminum hydroxide is prevented from clogging downstream components by neutralizing the completely reacted hydrolysate with hydrochloric or sulfuric acid, causing the dissolved aluminum to form a precipitate, which is then filtered (Step 7). The hydrolysate is sent to holding tanks to await secondary treatment in the SCWO reactors. 

This reaction is achieved by heating the monohaloalkane under reflux with ethanollc potassium (or sodium) hydroxide, i.e. potassium (or sodium) hydroxide dissolved in ethanol. The reaction is referred to as a base-induced elimination reaction and to demonstrate more clearly the role of the base in the reaction, it is worth considering the mechanism involved. This is illustrated for the reaction between 2-bromopropane and ethanolic potassium hydroxide ... 

The residue after the water wash is leached at an elevated temperature by sulfuric acid, part of which is the recycled raffinate from the vanadium extraction. The leaching yield of vanadium (mainly IV-valent) is about 55% and of nickel about 95%. A final (post) leach with sodium hydroxide dissolves the remaining vanadium (mainly V-valent). The resulting leach solution, containing practically all the vanadium ( 25gdm ) and nickel ( 12gdm ) is fed to the solvent extraction circuit. 

Substances typical of acids and bases are, respectively, HCl and NaOH. Hydrogen chloride dissolves in water with practically complete dissociation into hydrated protons and hydrated chloride ions. Sodium hydroxide dissolves in water to give a solution containing hydrated sodium ions and hydrated hydroxide ions. Table 3.6 gives values of the mean ionic activity coefficients, y , at different concentrations and indicates the pH values and those expected if the activity coefficients are assumed to be unity. 

Sodium hydroxide dissolves in water to give OH (aq) ions, the strongest base which can exist in an aqueous system. Chloric(VII) acid (perchloric acid) dissociates practically completely in dilute solution to give H30+(aq) ions, which represent the strongest acid which can exist in an aqueous system. The amphoteric behaviour of aluminium is noticed in a series of hydrated salts containing the Al3 + ion and in compounds such as NaA102, which contains the aluminate(III) ion, AIO2-. 

To a flask are added with stirring 6.8 gm (0.06 mole) of 2-mercaptoethylamine hydrochloride in 35 ml of 95 % ethanol, 2.5 gm (0.06 mole) of sodium hydroxide dissolved in 4 ml of water, and then 6.8 gm (0.05 mole) of phenyl isothiocyanate. The temperature rises to about 39°C and then slowly drops to room temperature. After 2 hr at room temperature the mixture is poured into 200 ml of ice water, the solid is filtered, washed with water, and dried to give 9.7 gm (91 %), m.p. 105°-114°C of crude l-(2-mercaptoethyl)-3-phenyl-2-thiourea. The product is recrystallized twice from ethanol to give crystals melting at 113°-116.5°C. 

Iron(III) oxide or alumina is refined from bauxite. Approximately 175 million tons of bauxite are mined annually worldwide, with virtually all of this processed into alumina. Alumina is a white crystalline substance that resembles salt. Approximately 90% of all alumina is used for making aluminum, with the remainder used for abrasives and ceramics. Alumina is produced from bauxite using the Bayer process patented in 1887 by Austrian Karl Josef Bayer (1847-1904). The Bayer process begins by grinding the bauxite and mixing it with sodium hydroxide in a digester. The sodium hydroxide dissolves aluminum oxide components to produce aluminum hydroxide compounds. For gibbsite, the reaction is Al(OH)3 + NaOH —> Al(OH)4 + Na+. Insoluble impurities such as silicates, titanium oxides, and iron oxides are removed from the solution while sodium hydroxide is recovered and recycled. Reaction conditions are then... 

The submitters observed the separation of a pasty solid at this stage and added four 10-ml. portions of water during the addition of- the thiol, then dissolved the entire solid with approximately 240 ml. of water. Sometimes, at this point, as much as 10% of the added thiol separated out as a floating oil. The presence of this thiol affects the course of the reaction to yield symmetrical disulfides.2 In this case the organic layer should be separated, then added dropwise to an equivalent amount of sodium hydroxide dissolved in a minimum amount of water, and mixed with the original thiolate solution. 

According to G. Calcagni, 100 c.c. of a cold 66 per cent, of sodium hydroxide dissolves 24 55 grms. of sulphur or 57 parts of sulphur per 23 parts of sodium while 100 c.c. of a similar soln. of potassium hydroxide dissolves 17 70 grms. of sulphur, or 59 35 parts of sulphur per 39 15 parts of potassium. The soln. reacts for sulphides, polysulphides, thiosulphates, and sulphites. The reaction between alkali hydroxides and sulphur is complex probably sulphides are first formed from which thiosulphates are produced, and by the dissolution of more sulphur, polysulphides the thiosulphates Ipse part of their sulphur forming sulphites. In the more cone. soln. of sulphur part of the latter appears to be uncombined because these soln. yield sulphur to hot benzene. All the soln. are decomposed by carbon dioxide yielding sulphur and hydrogen sulphide. 

Powdered sodium hydroxide can be used in place of sodium methoxide with no appreciable change in yield. Sodium hydroxide dissolves less readily in methanol. 

Both the hydrolysis of nitrocellulose by means of hydroxides and the hydrolytic decomposition of butyl nitrate, as established by Merrow et ah, proceeds very slowly. For example, if a 0.1 M solution of butyl nitrate is hydrolysed at a temperature of 26.9°C by the action of 0.2 M sodium hydroxide dissolved in 60% ethanol, then after 16 days, only about 10% has entered into the reaction. With the addition of hydrosulphide, the process is completed within a period of 4 hr. 

The amine hydrochloride solution is evaporated nearly to dryness on a steam bath (Note 13) and transferred with about 300 ml. of water to a 1-1. threc-necked flask equipped with a stirrer,3 separatory funnel, and condenser. The stirrer is started, and the acid solution is cooled to 0° by immersing the flask in an ice bath. The amines are liberated by adding slowly 100 g. of sodium hydroxide dissolved in 250 ml. of water. 

Sodium aesenite is prepared by dissolving 226 g. (1.14 moles) of powdered arsenious oxide, made into a paste with a little water, in a solution of 275 g. (6.88 moles) of sodium hydroxide dissolved in 600 cc. of water. This solution, diluted with 600 cc. of water, is poured into a 2-1. three-neck flask, provided with a reflux condenser and a mechanical stirrer, and 150 g. (1.22 moles) of freshly distilled nitrobenzene is added (Note 1). 

Alkali metal alkoxides and phenoxides may be obtained by reacting the metal hydroxide with either alcohol or phenol. With alcohols the generated water must be removed, typically as an azeotrope, as with sodium hydroxide dissolved in ethanol-benzene followed by reflux.69 With the more acidic phenols the phenoxides of Li, Na, K, Rb and Cs are more readily formed by simply heating MOH in absolute ethanol with phenol followed by recrystallization.70"72... 

The sodium hydroxide dissolved completely (aq = aqua, English water) and separated into ions. The equation is not yet complete, however. That is only the case when there are equal numbers of atoms of the same kind both to the left and the right of the arrow. In addition, the charges on both sides of the arrow have to be equal. In other words an equation must meet the law of conservation of mass and charge . This can only be achieved by placing as small as possible whole numbers in front of the substances, the so-called coefficients. 

---