原題有問題,酸多堿少,溶液應(yīng)為酸性.估計體積比是2:3.下面按2:3計算.
設(shè)原溶液濃度為x mol/L,鹽酸和氫氧化鈉溶液體積分別為400和600毫升.并假定混合后的體積是鹽酸和氫氧化鈉溶液體積之和 (1000毫升,1L) .
HCl:0.400x mol
NaOH:0.600x mol
NaOH + HCl === NaCl + H2O
反應(yīng)后剩NaOH:0.600x - 0.400x = 0.200x mol
pH = 12,
[H+] = 10^(-12)
[OH-] = 10^(-14)/10^(-12) = 10^(-2)
[OH-] = 0.200x/1 = 0.2x = 10^(-2)
x = 0.050 mol/L