Question

Find the combined pH of the mixture.​

Answer 1

Answer:

Example #1: Calculate the pH of a solution obtained by mixing 100. mL of an acid of pH = 3.00 and 400. mL solution of pH = 1.00.

Solution:

1) Determine total moles of H+ in solution:

for pH = 3.00, [H+] = 0.0010 M

for pH = 1.00, [H+] = 0.10 M

(0.0010 mol/L) (0.100 L) = 0.00010 mol

(0.10 mol/L) (0.400 L) = 0.040 mol

0.040 mol + 0.00010 mol = 0.0401 mol

Note: we ignore the H+ contribution from water.

2) Determine the [H+] of the combined solution:

0.0401 mol / 0.500 L = 0.0802 M

3) Determine the new pH:

pH = −log 0.0802 = 1.096