Which of the following substances will increase the molar solubility of nickel(II) phosphate in a saturated solution?
Na3PO4
HNO3
NH4Cl
(NH4)3PO4
KOH
HNO3
To determine which substance will increase the molar solubility of nickel(II) phosphate, we need to consider the common ion effect and the reaction between the substances and nickel(II) phosphate.
1. Na3PO4: Adding sodium phosphate (Na3PO4) to a saturated solution of nickel(II) phosphate will increase the molar solubility. This is because the phosphate ion (PO4^3-) will react with nickel(II) phosphate (Ni3(PO4)2) to form a soluble complex ion.
2. HNO3: Nitric acid (HNO3) will not increase the molar solubility of nickel(II) phosphate since HNO3 does not contain any ions that can form a soluble complex with nickel(II) phosphate.
3. NH4Cl: Adding ammonium chloride (NH4Cl) to a saturated solution of nickel(II) phosphate will not increase the molar solubility. The chloride ion (Cl-) is not expected to react with nickel(II) phosphate to form a soluble complex.
4. (NH4)3PO4: Adding ammonium phosphate ((NH4)3PO4) to a saturated solution of nickel(II) phosphate will also increase the molar solubility. The phosphate ion (PO4^3-) will react with nickel(II) phosphate (Ni3(PO4)2) to form a soluble complex.
5. KOH: Potassium hydroxide (KOH) will not increase the molar solubility of nickel(II) phosphate since KOH does not contain any ions that can form a soluble complex with nickel(II) phosphate.
Therefore, the substances that will increase the molar solubility of nickel(II) phosphate in a saturated solution are Na3PO4 and (NH4)3PO4.
To determine which of the substances will increase the molar solubility of nickel(II) phosphate, we need to understand the concept of common ion effect.
The common ion effect states that the solubility of a salt is decreased by the presence of a common ion in the solution. A common ion is an ion that is already present in the solution either as a result of a dissociated compound or through the addition of another compound containing the ion.
Now, let's consider each substance in the question and analyze their ions:
1. Na3PO4: Sodium phosphate is a compound that dissociates into sodium ions (Na+) and phosphate ions (PO43-). Since the nickel phosphate solution already contains phosphate ions (PO43-), adding additional phosphate ions would increase the concentration of the common ion, reducing the molar solubility of nickel(II) phosphate. Therefore, Na3PO4 would not increase the molar solubility of nickel(II) phosphate.
2. HNO3: Nitric acid dissociates into hydrogen ions (H+) and nitrate ions (NO3-). Since neither of these ions is common to the nickel phosphate solution, adding nitric acid would not significantly affect the molar solubility of nickel(II) phosphate.
3. NH4Cl: Ammonium chloride dissociates into ammonium ions (NH4+) and chloride ions (Cl-). Similar to the first case, the addition of chloride ions (Cl-) would increase the concentration of the common ion. Therefore, NH4Cl would not increase the molar solubility of nickel(II) phosphate.
4. (NH4)3PO4: Ammonium phosphate dissociates into ammonium ions (NH4+) and phosphate ions (PO43-). As explained in the first case, the addition of phosphate ions (PO43-) increases the concentration of the common ion. Therefore, (NH4)3PO4 would not increase the molar solubility of nickel(II) phosphate.
5. KOH: Potassium hydroxide dissociates into potassium ions (K+) and hydroxide ions (OH-). Since neither of these ions is common to the nickel phosphate solution, adding potassium hydroxide would not significantly affect the molar solubility of nickel(II) phosphate.
Based on the analysis above, none of the substances mentioned (Na3PO4, HNO3, NH4Cl, (NH4)3PO4, and KOH) will increase the molar solubility of nickel(II) phosphate in a saturated solution.