The solution of a salt is basic. The salt must be

Options

A. `KNO_3`
B. `NaCN`
C. `CH_3 COONH_4`
D. `NH_4 NO_3`

Answer

To determine which salt solution is basic, we can analyze the nature of the ions produced when the salt dissociates in water. Here’s a step-by-step solution:

### Step 1: Understand Salt Dissociation
Salts dissociate into their respective cations and anions when dissolved in water. For example, if we take the salt NaCN, it dissociates into Na⁺ and CN⁻ ions.

**Hint:** Remember that salts are formed from the neutralization of acids and bases, and they can produce either acidic, basic, or neutral solutions based on the strength of the parent acid and base.

### Step 2: Identify the Strength of the Parent Acid and Base
Next, we need to consider the strength of the acids and bases from which the salt is derived. A strong base and a weak acid will result in a basic solution. For example:
- NaOH (strong base) and HCN (weak acid) produce NaCN, which is basic.
- KOH (strong base) and HNO3 (strong acid) produce KNO3, which is neutral.

**Hint:** Strong bases tend to dominate the pH of the solution when paired with weak acids.

### Step 3: Analyze the Example of NaCN
In the case of NaCN:
- Na⁺ comes from NaOH (strong base).
- CN⁻ comes from HCN (weak acid).
When NaCN is dissolved in water, the CN⁻ ion can react with water to produce OH⁻ ions, making the solution basic:
\[ CN^- + H_2O \rightleftharpoons HCN + OH^- \]

**Hint:** Look for the ions that can produce hydroxide ions (OH⁻) when dissolved in water.

### Step 4: Conclusion
Based on the analysis, the salt that produces a basic solution must be one where the cation is from a strong base and the anion is from a weak acid. Therefore, salts like NaCN or KCN will result in a basic solution.

**Final Answer:** The salt must be a salt formed from a strong base and a weak acid (e.g., NaCN).