Question

Equal volume. Of mixture of 2 solution with ph = 2 and ph = 12 find out the ph of the resultant mixture

Answer 1

pH 2 is(H^+) = 10^-2 M
pH 12 is(H^) = 10^-12 M

Assume a volume of 100 mL (0.1 L) of each, then
mols pH 2 soln = M x L = 0.01 x 0.1 = 0.001 mols.
mols pH 12 soln = 0.000000000001 x 0.1 = very small.

Add the two volumes and you have 200 mL (0.2L) of essentially 0.001 mols so (H^+) = mol/L = 0.001/0.2 = 5E-3
pH = ?