Calculation of pH value
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500ML, 0.04g NaOH, determine the pH value. This is from inorganic chemistry; may I ask for the steps?
This post was last edited by zhangyong6404 on 2009-11-6 at 14:42. First, calculate the number of moles of NaOH: 0.04 ÷ 40 = 0.001 (mol). Then, calculate the molar concentration of NaOH in the solution: 0.001 ÷ 0.5 = 0.002 (mol/L). NaOH is a strong monobasic base, and it is assumed to be completely ionized. Therefore, the molar concentration of -] is 0.002 mol/L = 10-14; hence, 10-14/0.002 = 5×10-11. PH = -lg[+] = lg(5×10-11) = 10.3
Please, go and read the inorganic chemistry textbook first
The calculation method is correct, but the result is wrong; it should be 12-lg5
The result is indeed 12-lg5; the moderator was careless.