0.250 g KCN is dissolved in 50 mL of water, and added to 2 mL of NaOH then mixed with 48mL of water. What is the molar concentration of KCN?

I am stuck on this question.
So far I have:
0.250gKCN/0.050L= 5M(g/L)

Moles of KCN: 5M = mol/0.05L = 0.25mol KCN

I am not sure exactly where to go from here or if I am on the right track. The addition of NaOH threw me off. If you can point me in the right direction it would be much appreciated.

1 answer

Do you want concn in M or g/L. I will assume you want molarity = M
mols KCN = grams/molar mass KCN = ?
Then ?mols/0.052 L = ? mols/L = M KCN. The NaOH just adds 2 mL to the total volume.