Hydroxide ions from strong base

Even though the strong acid and strong base in Sample Problem 1 are different from those in the HCl reaction with NaOH, the net ionic equation is the same. Hydrogen ions from the acid react with hydroxide ions from the base to form water. This equation is always the net ionic equation for a strong acid-strong base reaction. 

This molecule behaves as an acid in that it can donate a hydrogen ion, created from the hydrogen atom bonded to the positively charged nitrogen atom. What are all the products formed when 1 mole of this salt reacts with 1 mole of sodium hydroxide, NaOH, a strong base ... 

Hydroxides, such as sodium hydroxide and calcium hydroxide, are also strong bases in water. However, there is an interesting point here if an OH" ion accepts a proton from a water molecule, the water molecule donating the proton becomes a hydroxide ion, so there is no net change ... 

The correct answer is (B). From a conceptual perspective, remember that to neutralize an acid you must add enough strong base so that all of the hydrogen (hydronium) ions in the acid combine with the hydroxide ions of the base to form water. Therefore, if you determine the number of moles of hydroxide ions you add to the mixture during the titration, this should equal the number of moles of acid when the solution is neutral. 

Bases provide hydroxide ions to aqueons solntion. Soluble metal hydroxides, including those of the alkali metals and barium, are examples. The soluble metal hydroxides are ionic even when they are pure solids they remain ionic in water. When they are dissolved in water, the hydroxide ions are totally separated from the metal ions. A soluble metal hydroxide is a strong base. A weak base is not 100% ionized. Ammonia, the most common weak base, reacts with water to a small extent to provide hydroxide ions ... 

When salts derived from strong bases and weak acids are dissolved in water, the resulting solutions are always basic. This is because anions of weak acids react with water to form hydroxide ions. Consider a solution of sodium acetate, NaCH3COO, which is the salt of the strong base NaOH and the weak acid CH3COOH. It is soluble and dissociates completely in water. 

Addition of hydride ion from the catalyst gives the adsorbed dianion (15). The reaction is completed and product stereochemistry determined by protonation of these species from the solution prior to or concurrent with desorption. With the heteroannular enolate, (13a), both cis and trans adsorption can occur with nearly equal facility. When an angular methyl group is present trans adsorption (14b) predominates. Protonation of the latter species from the solution gives the cis product. Since the heteroannular enolate is formed by the reaction of A" -3-keto steroids with strong base " this mechanism satisfactorily accounts for the almost exclusive formation of the isomer on hydrogenation of these steroids in basic media. The optimum concentration of hydroxide ion in this reaction is about two to three times that of the substrate. 

Bases, like acids, are classified as strong or weak. A strong base in water solution is completely ionized to OH- ions and cations. As you can see from Table 4.1, the strong bases are the hydroxides of the Group 1 and Group 2 metals. These are typical ionic solids, completely ionized both in the solid state and in water solution. The equations written to represent the processes by which NaOH and Ca(OH)2 dissolve in water are... 

Any strong acid that may be present is first neutralised. Then, by selecting an appropriate base, whose conjugate acid has a Ka of about 10 5, the equilibrium for the tripositive cations will be forced to the right the base is too weak, however, to remove the hydroxonium ions from the equilibrium of the dipositive cations. Since a large excess of the basic ion is added, a basic salt of the tripositive metal usually precipitates instead of the normal hydroxide. Acetate or benzoate ions (in the form of the sodium salts) are the most common bases that are employed for this procedure. The precipitation of basic salts may be combined with precipitation from homogeneous solution, and thus very satisfactory separations may be obtained. 

The net outcome of any neutralization reaction between a strong acid and a strong base in water is the formation of water from hydrogen ions and hydroxide ions. 

FIGURE 1.3 The net ionic equation for the neutralization of HCN, a weak acid, by the strong base NaOH, tells us that the hydroxide ion extracts a hydrogen ion from an acid molecule. 

An aqueous solution of potassium hydroxide contains K , OH, and H2 O. Phosphoric acid is a weak acid, so most of its molecules remain as H3 PO4 in aqueous solution. The species present at the beginning of the reaction are K and OH ions and molecules of H3 PO4 and H2 O. The hydroxide ion is a powerful base that removes all of the acidic hydrogen atoms from both strong and weak acids. 

In one type of titration, a solution of a strong base such as sodium hydroxide is added slowly to a solution that contains an unknown amount of an acid. Each hydroxide ion added to the acid solution accepts one proton from a molecule of acid. As the titration proceeds, fewer and fewer acid molecules remain in the acid solution, but the solution is still acidic. At the stoichiometric point, just enough hydroxide ions have been added to react with every acidic proton present in the acid solution before the titration was started. The hydroxide ions in the next drop of titrant do not react because acid molecules are no longer present in the solution. Before the stoichiometric point, the solution contains excess acid. After the stoichiometric point, the solution contains excess OH". Figure 4-11 shows a titration setup and molecular views illustrating titration of a strong acid by a strong base. 

For any aqueous strong base, the hydroxide ion concentration can be calculated directly from the overall solution molarity. As is the case for aqueous strong acids, the hydronium and hydroxide ion concentrations are linked through the water equilibrium, as shown by Example. ... 

To draw molecular pictures illustrating a proton transfer process, we must visualize the chemical reactions that occur, see what products result, then draw the resulting solution. When a strong base is added to a weak acid, hydroxide ions remove protons from the molecules of weak acid. When more than one acidic species is present, the stronger acid loses protons preferentially. 

Hydroxide Ion Is a strong base and acetic acid Is a weak acid, so proton transfer from CH3 CO2 H to OH goes essentially to completion ... 

To complete the deionization process, water from the cation unit is passed through a strong base anion exchange resin in the hydroxide form. The resin exchanges hydrogen ions for both highly ionized mineral ions and the more weakly ionized carbonic and silicic acids according to1,2 ... 

Bromomethyl-5-nitrofuran offers an incoming nucleophile a choice of reaction sites product formation seems to be determined mainly by the nature of the nucleophile but is also strongly dependent upon the solvent and other conditions. The hard base hydroxide ion removes a methylenic proton from the active methylene group and the new nucleophile displaces bromide from another molecule to produce, eventually, the bis(5-nitro-2-furyl)ethene (Scheme 35, A).191... 

The solution of a salt derived from a strong base and weak acid is basic because the anion of a weak acid reacts with water (hydrolysis) to form hydroxide ions. Consider the soluble salt NaCIO found in chlorine bleaches prepared by reacting NaOH, a strong base, and HC10, a weak acid. The salt dissociates completely in water and the conjugate base of the weak acid, CIO-, hydrolyzes, producing OH- ions. 

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