Yes, potassium phosphate is soluble in water.
Potassium phosphate (K₃PO₄) readily dissolves in water. This is determined by examining the chemical composition of the compound and applying general solubility rules, which is the process shown in the reference where the potassium ion (K⁺) and the phosphate ion (PO₄³⁻) are identified on a chart.
Understanding Solubility
Solubility refers to the ability of a substance (the solute) to dissolve in a solvent, forming a homogeneous solution. For ionic compounds like potassium phosphate, this process involves the separation of the positively charged potassium ions and the negatively charged phosphate ions by the polar water molecules.
Key Components of Potassium Phosphate
To determine the solubility of an ionic compound, we look at its constituent ions. As highlighted in the reference, we identify:
- Positive Ion (Cation): Potassium ion (K⁺)
- Negative Ion (Anion): Phosphate ion (PO₄³⁻)
| Component | Chemical Formula | Charge |
|---|---|---|
| Potassium Ion | K⁺ | +1 |
| Phosphate Ion | PO₄³⁻ | -3 |
| Potassium Phosphate | K₃PO₄ | Neutral |
Why Potassium Phosphate is Soluble
General solubility rules in chemistry provide guidelines for predicting whether an ionic compound will dissolve in water. One of the most important rules states:
- Salts containing alkali metal ions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺) are generally soluble. Potassium (K⁺) is an alkali metal ion.
While many phosphates (salts containing the PO₄³⁻ ion) are typically insoluble (e.g., calcium phosphate, iron phosphate), phosphates of alkali metals are a notable exception to this rule.
Thus, the presence of the potassium ion (K⁺) ensures that potassium phosphate (K₃PO₄) is soluble in water, dissolving to form K⁺ and PO₄³⁻ ions in solution. The reference's method of using a chart to find the intersection of K⁺ and PO₄³⁻ confirms this standard approach to determining solubility based on the ions present.
