The pH of the salt solution.

. Network salic solution pHin addition to strong acid and alkali salts no hydrolytic reaction, according to
acid-base
proton theory, the hydrolytic reaction of various other salts, the essence is a proton transfer reaction, that is, acid-base reaction. In pure water, the H-plus is equal to the OH-, neutral.
the ions and H-plus and OH-effects added to the salt change the concentration of H-plus or OH-in the water, so the solution of most salts shows acidity or alkalinity. The ions of this salt and the water H-plus or OH-act to produce a difficult-to-dissophate substance, so that the water's reaction to change is called salt hydrolysaling. The acidity and alkalinity after hydrolysalization are also different due to the difference between the strength of the salt and the base.1, the PH value of the strong alkali weak acid solution1 strong alkali weak acid solution, such as NaOAc solution: NaOAc→Na-OAc-Na plus does not bind with the hydroelectric out of oh-na, it is not related to the acidity and alkalinity of the solution. OAc- is hoAc's conjugated alkali, which releases OH with water action - making the solution alkaline.pH of a strong alkali salt solution with multiple weak acids is similar to that of a meta-strong alkali weak acid. Due to Kb1 Kb2, the solution in the solution is mainly produced by the first-stage alkaline dissoluation, while the second-stage alkaline dissoqueration produces very little OH-and weak acids, can be ignored. At the time of calculation, the Kb in the Kb1 generation (2-4) can be calculated. For example, the concentration ofna2CO3 in the Na2CO3 solution is 0.100mol L-, c/Kb1,0.100/1.78×10-4>500, and the formula (2-4) is calculated pOH=2.37 pH=14-2.2.2 37 s 11.63II, strong acid weak alkali salt solution pHone strong acid weak alkali salt, e.g. NH4CL solution: NH4 plus ions are conjugated acids of NH3, it is ionized in water:or short as CL-ions are not associated with hydroelectric ionization of H-plus, it is not related to the alkali acidity of the solution. It can be considered that NH4 plus is acid, and water release h plus and make the solution appear acidic. When the c/ka ≥ 500, the available formula (2-3) is calculated., c is the concentration of hydrochloric acid. The PH value can be calculated by the H-plus.pH in a multi-strength acid weak alkali salt such as (NH4) 2SO4 solution is similar to the pH calculation of a meta-strong acid weak alkali salt.three, the PH value of the two-sex substance solution(i) the pH value of the plucoic acid solutionthe acidic acid ions in the plural acid salt, e.g. HCO-3 in the aqueous solution of the proton transfer balance is as follows: HCO-3 as an acid, according to mathematical reasoning, when Ka2C> At >20KW, and c>20Ka1, the dissocation of water can be ignored, and the concentration of substances of both sexes is not very rare, the approximate calculation of HCO-3 solution is(3-9)type Ka1 and Ka2 are carbonic acid first and second-stage ionization constants, respectively.can also be derived by analogy for other acidic root ion aqueous water solutions and PH values. For example, for H2PO4 solutions:for HPO2-4 solutionsfrom these approximate formulas, the pH values of these salt solutions are independent of concentration.1 calculates the pH of the 0.10mol.L-1NaHCO3 solution. Known as H2CO3, Ka1 is 4.30 x 10-7, Ka1 is 5.61 x 10-11.


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