As a chemistry expert, I'm here to provide you with a detailed explanation of the nature of sodium cyanide (NaCN) and its behavior in aqueous solutions.

Sodium cyanide (NaCN) is a salt that is formed from the reaction between a strong base, sodium hydroxide (NaOH), and a weak acid, hydrocyanic acid (HCN). In aqueous solutions, salts derived from strong bases and weak acids tend to hydrolyze, which means that they react with water to form a basic solution. This is due to the fact that the anion from the weak acid (in this case, the cyanide ion, CN^-) can accept a proton (H^+) from water, forming the weak acid (HCN) and hydroxide ions (OH^-), which are the conjugate base of water and a strong base.

The pH of a 0.1 M solution of NaCN being 11.1 indicates that the solution is indeed basic. This is because the cyanide ion, being a weak base, readily accepts a proton from water to form the conjugate acid, HCN, and hydroxide ions. The presence of hydroxide ions in the solution is what causes the solution to have a pH greater than 7, which is the characteristic of a basic solution.

It's important to note that the strength of an acid or a base is determined by its ability to donate or accept protons. In the case of NaCN, the cyanide ion (CN^-) is a weak base because it has a low tendency to accept protons. However, when it does accept a proton, it forms HCN, which is a weak acid because it has a low tendency to donate protons.

The process of hydrolysis can be represented by the following chemical equation:

\[ \text{CN}^- + \text{H}_2\text{O} \rightleftharpoons \text{HCN} + \text{OH}^- \]

This equation shows that the cyanide ion reacts with water to form hydrocyanic acid and hydroxide ions. The hydroxide ions are responsible for the basic nature of the solution.

In summary, NaCN is not a base itself but a salt that forms a basic solution when dissolved in water due to the hydrolysis of the cyanide ion. The formation of hydroxide ions as a result of this hydrolysis reaction is what imparts the basic character to the solution.

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The pH of a 0.1 M solution of NaCN has a pH = 11.1. How can this solution be basic? Notice what happens here, the cyanide ion accepts a proton from water to form its conjugate acid, HCN, and hydroxide, the strongest base that exists in water. It is this prescence of hydroxide that makes the salt solution basic.read more >>