We’re being asked to determine the concentration of cyanide ions (CN-) in the mixture of 0.50 M HCN and 2.00 M HNO2.
HNO2 has a higher Ka value there most of the H3O+ ions will come from HNO2. Knowing this, we’re going to calculate the concentration of cyanide ions using the following steps:
Step 1: Construct an ICE chart for the ionization of HNO2 and write the Ka expression.
Step 2: Calculate the H3O+ concentration.
Step 3: Construct an ICE chart for the ionization of HCN and write the Ka expression.
Step 4: Calculate the CN- concentration.
A mixture of two weak acids contains 0.50 M HCN (Ka = 6.2 x 10-10) and 2.00 M HNO2 (Ka = 4.4 x 10-4). What is the concentration of cyanide ions in this mixture?
A. 2.8 x 10-4 M
B. 1.0 x 10-8 M
C. 1.4 x 10-6 M
D. 3.0 x 10-2 M
E. 1.8 x 10-5 M
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.