00:01
To determine the ka value, we first need to calculate the hydronium concentration.
00:06
Percent ionization is equal to the hydronium concentration divided by the concentration of the acid times 100.
00:16
So the hydronium concentration will simply be equal to the percent multiplied by the concentration of ha divided by 100.
00:28
The percent they tell us is 17 .5.
00:32
We'll multiply that by the concentration of 0 .100 and then divide by 100 and this gives us 0 .0175 molar.
00:46
Then the ka value by definition is equal to the hydronium concentration squared divided by the concentration of the acid minus the hydronium concentration.
00:59
So that'll be equal to 0 .0175 squared divided by 0 .100 minus 0 .0175 and we get a ka value of 3 .71 times 10 to the negative 3.
01:22
The ph is then just the negative log of the hydronium concentration or the negative log of 0 .0175 which gives us 1 .756, 1 .76.
01:43
Then it wants to know what would be the percent ionization when the concentration of the acid is increased to 0 .5...