Final answer:
Sodium cyanide generates toxic hydrogen cyanide gas when in contact with water. The chemical reaction between hydrocyanic acid and potassium hydroxide neutralizes the acid to produce water and potassium cyanide. The cyanide anion is a weak base and forms a basic solution in water.
Step-by-step explanation:
When sodium cyanide (UN1689) is spilled in water, it generates hydrogen cyanide gas (HCN), which is highly toxic. If you're referring to Table 1 for distances, it's likely that you're looking at evacuation distances or isolation zones that are relevant in the event of a spill or leak, as prescribed by safety and emergency response guidelines. Hydrogen cyanide, when formed in this way, poses significant risks due to its potential to release as a gas and its ability to inhibit cellular respiration.
Hydrocyanic acid (HCN(aq)) can be neutralized by potassium hydroxide (KOH(aq)) in a reaction that forms water and a salt. The balanced chemical equation is: HCN(aq) + KOH(aq) → K+ + CN− + H2O(l). The salt produced in this reaction is potassium cyanide (KCN).
It's important to understand the behavior of cyanide in aqueous solutions. While the cations (such as K+ and Na+) associated with cyanide salts do not contribute to acidity or basicity, the anion cyanide (CN−) is a weak base and the conjugate base of hydrogen cyanide. This means CN− in solution can react with water, producing a basic solution due to the generation of hydroxide ions (OH−).