# Question #a721d

##### 2 Answers

pH = 1.61151

HF = 0.855538M

#### Explanation:

We can find the concentration of

One is by the ICE table (but this is a 5% rule) and the other is square root which is absolutely correct and the other is Ostwald's law of dillution

Let's set up an ICE table.

Ka =

You can ignore x

Ka =

Step 1: Multiply both sides by -x+0.88.

x=

x = 0.02412457847582909 This is the

Another way I told you is very simple

You can see that -x matters so much

Therefore the concentration of HF

0.88M - x(you remember, we did this in the ice table above) = 0.88M - 0.024462M = 0.855538M

You can see that -x matters so much

Third way is

Ostwald's law of dillution

degree of ionization or

Plug in the variables

Now to calculate

You know that for any substance in water at 298K the

Note there are two ways to solve pH . One way is that

And then you can subtract the pOH from 14

And if you add these you get a perfect 14

#### Explanation:

**Method 1. Using the 5 % approximation**

Let's set up an ICE table.

**Test for negligibility**

∴

Since

Then

**Method 2. Solving the quadratic**

We had the expression

**Conclusion**

Within the limitations of the allowed significant figures, the approximate method gives the same result as solving the quadratic.