Problem: A mixture of acids is made that has 0.100 M HCHO 2 and 0.050 M HClO. The Ka for HCHO2 is 1.8 x 10 -4, and the Ka for HClO is 2.9 x 10 -8. Solve for the pH of the mixture of acids.A) 2.37B) 0.82C) 1.00D) 4.42

🤓 Based on our data, we think this question is relevant for Professor Bindell's class at UCF.

FREE Expert Solution

We are asked to solve for the pH of the mixture of acids.


Calculate the [H3O+] 0.100 M HCHO2

Ka = productsreactantsKa =[CHO2-][H3O+][HCHO2]1.8 × 10 -4 =(x)(x)0.100-x

Check if x is negligible in the denominator: 

0.1001.80×10-4 = 555.56 >500 assume x is negligible

1.8 × 10 -4 =(x)(x)0.1001.8 × 10 -4 =x20.100x2 = (1.8 × 10 -4)(0.100)x = (1.8 × 10 -4)(0.100)

[H3O+] = x = 4.24 x 10-3 M


Next, do the same procedure for 0.050 M HClO 


Ka = productsreactantsKa =[ClO-][H3O+][HClO]2.9 × 10 -8 =(x)(x)0.050-x

Check if x is negligible in the denominator: 

0.0502.90×10-8 = 1724137.93 >500 assume x is negligible


2.9 × 10 -8 =(x)(x)0.0502.9 × 10 -8 =x20.050x = (2.9 × 10 -8)(0.050)

[H3O+] = x = 3.8 x 10-5 M


View Complete Written Solution
Problem Details

A mixture of acids is made that has 0.100 M HCHO 2 and 0.050 M HClO. The Ka for HCHO2 is 1.8 x 10 -4, and the Ka for HClO is 2.9 x 10 -8. Solve for the pH of the mixture of acids.

A) 2.37

B) 0.82

C) 1.00

D) 4.42

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Weak Acids concept. If you need more Weak Acids practice, you can also practice Weak Acids practice problems.

What professor is this problem relevant for?

Based on our data, we think this problem is relevant for Professor Bindell's class at UCF.