Sodium oxide basicity

In contrast to the diversity in compositions encountered in the unrelated specimens above, all 45 samples of uncolored or amber glass with grisaille painting from the Chateau of Rouen were basically similar in composition. This glass contains about 15% potassium oxide and only about 3.5% sodium oxide (see Table II). Because these similar specimens came from the same building, a common source of manufacture seems likely. These data therefore support our belief that individual sources of glass produced compositionally consistent products. 

The appearance of proton on the left-hand side of the equation requires a cationic species on the right-hand side, and the solubility of Mg(OH)2 in acids depends upon the stability of Mg2+(aq) in acid solution. If the pH is raised to about 7, Mg(OH)2 is precipitated and this does not redissolve at alkaline pH Mg(II) forms no anionic species such as Mg(OH)4 (aq). Sodium oxide and magnesium oxide are classified as basic oxides. 

One of such scales has been proposed in [23]. This scale is based on Gibbs energy of the formation of sulphates from a basic oxide and sulphuric oxide SO3, and of sodium salts from acid and sodium oxides. The data are shown in Table 2.4. 

Different fluxes can be used. Basic fluxes employed for the attack of acidic materials include carbonates, hydroxides, peroxides, and borates. Oyrosulfates can be used as acidic flux. If an oxidizing flux is required, sodium peroxide can be used. As an alternative, small quantities of alkali nitrates or chlorates can be mixed with sodium carbonate. Basic and acidic fluxes are dissolved in an acid or basic medium, respectively. 

An oxide which with water forms a base is called a basic oxide. The oxides of the metals are basic oxides. Thus sodium oxide, Na O, reacts with water to form a base, sodium hydroxide ... 

Alumina presents a complication not important in chromia. Many commercial aluminas derive from basic solutions of alumina and retain substantial amounts of sodium oxide. Such base or base added to pure aluminas substantially modifies the catalytic character of alum-... 

Silicates are soluble because the sodium oxide (Na02) which is basic, keeps the pH at a level where silica (Si02) can be dissolved. If the pH is neutralized or lowered, the solubility of the silica is reduced, and it gels or polymerizes. Most silicate grouts depend upon such reactions. However, silicates can also react with salts such as calcium chloride to produce insoluble metal silicates or gels. 

Basic oxide sodium oxide phosphorus (Ill) oxide... 

The ore contains aluminium oxide (amphoteric) with large impurities of iron oxide (basic) and silicon dioxide (weakly acidic). The ore is treated with a hot 10% solution of sodium hydroxide, which reacts with the amphoteric aluminium oxide to form a solution of sodium aluminate. Iron oxide does not react as it is a base, and silicon dioxide does not... 

The former mechanism basically controls processes at temperatures lower than 650°C. With temperature increase the latter mechanism becomes more and more significant. The higher sodium temperature, the more vapour generation rate. The reaction zone extends from the sodium surface resulting in the decrease of heat transfer to sodium. This, in its turn, decreases evaporation rate. Studies have shown that steady state is achieved at the pool sodium temperature of 720°C to 745°C. During burning process 15 to 25% of the combustion product mass leaves the reaction zone in the form of fume. Nevertheless sodium mass remains almost constant because of simultaneous mass increase due to sodium oxidation. 

The fusibility characteristics of coal ash will vary with its chemical constituents. Most low-rank coals produce an ash high in basic metals and low in iron content. Therefore, they have a higher softening temperature, and consequently, are less susceptible to slagging. The behavior of ash is extremely complex, and while some constituent melt below 1040°C (1900°F), as the calcium and sodium content of the ash increases, the rate of deposition increases on tube surfaces. The sodium oxide content, in particular, can have a catalytic effect on the rate of deposition, and investigations have shown that ash with a sodium content above 5% fouls at an accelerated rate. 

The potassium oxide and sodium oxide are also hazardous materials they are both basic oxides that react with water to form very caustic potassium hydroxide and sodium hydroxide. 

SiOj, a third substance included in the gas-generating mixture of chemicals, is an acidic oxide that reacts with the basic potassium and sodium oxides, neutralizes their caustic characteristics, and converts them into a safe siUcate-glass powder. 

Soda ash decomposes to sodium oxide when heated. Sodium and calcium oxides, which are basic oxides, react with fused silicon dioxide, Si02, an acidic oxide, to produce silicate glass. 

Sodium oxide is a simple strongly basic oxide. It is basic because it contains the oxide ion, 0 , which is a very strong base with a high tendency to combine with hydrogen ions. 

Magnesium oxide is a simple basic oxide, because it also contains oxide ions. However, it is not as strongly basic as sodium oxide because tbe ionic bonding is stronger. 

One way to think of the process is in terms of a sequence from the metal oxide to the metal hydroxide that then dissociates into the aqueous hydroxide and metal ions. It follows that sodium oxide is a basic anhydride it produces the base sodium hydroxide in aqueous solution. Figure 11.12 shows some of the more common basic anhydrides and their corresponding bases. Note that the greater the degree of ionic character in the oxide, the more basic it is. In the next section, we discuss the nature of metal hydroxides and explore why they split to produce aqueous metal cations and hydroxide anions. 

CHsONa/MSU, NaOH/MSU, NaN3/MSU-y heterogeneous base catalysts were prepared and evaluated in biodiesel production. Excepting the NaNs/MSU catalyst, the thermodynamic equihbrium of about 60% was reached by each catalyst at the very beginning of the reaction. The catalytic activity of NaOH/MSU decrese rapidly, while for CHsONa/ MSU remained almost constant after 120 min time-on stream. Also, the most active and stable basic catalyst shows the most narrow resonance line at -20 ppm attributed to supported sodium oxide, which remains unaltered after reactioa... 

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