Problem: 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 MB. 1.0 x 10-8 MC. 1.4 x 10-6 MD. 3.0 x 10-2 ME. 1.8 x 10-5 M

FREE Expert Solution

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.

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Problem Details

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

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