Question

42. What is the [OH-] in the final solution prepared by
mixing 20.0 mL of 0.050 M HCI with 30.0 mL of
0.10 M Ba(OH),?
(1) 0.12 M
(2) 0.10 M
(3) 0.40 M
(4) 0.0050 M​

Answer 1

Answer:

Step-by-step explanation:

H+ ions present in HCl solution:  20.0/1000 * 0.050 = 0.001 moles

There are two OH- ions in a molecule of Ba (OH)2.

OH- ions released in the Barium Hydroxide solution =

       = 2 * 30.0/1000 * 0.10 = 0.006 moles

So 0.001 moles of H+ and OH- combine to form water.

So 0.005 moles of OH- remain. So the molarity of [ OH- ]

           = 0.005 moles / (20+30) ml   =0.100 M