Question

Which anion will form a precipitate with Ca2+

Answer 1

The anions that can form a precipitate with ${\mathbf{C}}{{\mathbf{a}}^{{\mathbf{2+}}}}$are $\boxed{{\text{SO}}_4^{2-},{\text{CO}}_3^{2-}}$

Further Explanation:

Precipitation reaction:

It is the type of reaction in which an insoluble salt is formed by the combination of two solutions containing soluble salts. That insoluble salt is known as precipitate and therefore such reactions are named precipitation reactions. An example of precipitation reaction is,

${\text{AgN}}{{\text{O}}_3}\left({aq}\right)+{\text{KBr}}\left({aq}\right)\to{\text{AgBr}}\left(s\right)+{\text{KN}}{{\text{O}}_3}\left({aq}\right)$

Here, AgBr is a precipitate.

The solubility rules to determine the solubility of the compound are as follows:

1. The common compounds of group 1A are soluble.

2. All the common compounds of ammonium ion and all acetates, chlorides, nitrates, bromides, iodides, and perchlorates are soluble in nature. Only the chlorides, bromides, and iodides of ${\text{A}}{{\text{g}}^+}$, ${\text{P}}{{\text{b}}^{2+}}$, ${\text{C}}{{\text{u}}^+}$ and ${\text{Hg}}_2^{2+}$ are not soluble.

3. All common fluorides, except for   and group 2A fluorides, are soluble. Moreover, sulfates except ${\text{CaS}}{{\text{O}}_{\text{4}}}$, ${\text{SrS}}{{\text{O}}_{\text{4}}}$, ${\text{BaS}}{{\text{O}}_{\text{4}}}$, ${\text{A}}{{\text{g}}_{\text{2}}}{\text{S}}{{\text{O}}_{\text{4}}}$ and ${\text{PbS}}{{\text{O}}_{\text{4}}}$ are soluble.

4. All common metal hydroxides except ${\text{Ca}}{\left({{\text{OH}}}\right)_{\text{2}}}$, ${\text{Sr}}{\left({{\text{OH}}}\right)_{\text{2}}}$, ${\text{Ba}}{\left({{\text{OH}}}\right)_{\text{2}}}$ and hydroxides of group 1A and that of transition metals are insoluble in nature.

5. All carbonates and phosphates, except those formed by group 1A and ammonium ion, are insoluble.

6. All sulfides, except those formed by group 1A, 2A, and ammonium ion are insoluble.

7. Salts that contain ${\text{C}}{{\text{l}}^-}$, ${\text{B}}{{\text{r}}^-}$ or ${{\text{I}}^-}$ are usually soluble except for the halide salts of ${\text{A}}{{\text{g}}^+}$, ${\text{P}}{{\text{b}}^{2+}}$ and ${\left({{\text{H}}{{\text{g}}_2}}\right)^{{\text{2+}}}}$.

8. The chlorides, bromides, and iodides of all the metals are soluble in water, except for silver, lead, and mercury (II). Mercury (II) iodide is water insoluble. Lead halides are soluble in hot water.

9. The perchlorates of group 1A and group 2A are soluble in nature.

10. All sulfates of metals are soluble, except for lead, mercury (I), barium, and calcium sulfates.

According to the solubility rules, the sulfates of calcium are insoluble in nature so sulfate ions $\left({{\text{SO}}_{\text{4}}^{{\text{2-}}}}\right)$form a precipitate with ${\text{C}}{{\text{a}}^{2+}}$.

The reaction between ${\mathbf{C}}{{\mathbf{a}}^{{\mathbf{2+}}}}$and ${\mathbf{SO}}_{\mathbf{4}}^{{\mathbf{2-}}}$ is as follows:

${\text{C}}{{\text{a}}^{2+}}\left({aq}\right)+{\text{SO}}_4^{2-}\left({aq}\right)\to{\text{CaS}}{{\text{O}}_4}\left(s\right)$

Also, the carbonates of calcium are insoluble. So carbonate ions $\left({{\text{CO}}_{\text{3}}^{{\text{2-}}}}\right)$form precipitate with ${\text{C}}{{\text{a}}^{2+}}$.

The reaction between ${\mathbf{C}}{{\mathbf{a}}^{{\mathbf{2+}}}}$and ${\mathbf{CO}}_{\mathbf{3}}^{{\mathbf{2-}}}$ is as follows:

${\text{C}}{{\text{a}}^{2+}}\left({aq}\right)+{\text{CO}}_3^{2-}\left({aq}\right)\to{\text{CaC}}{{\text{O}}_3}\left(s\right)$

There are many other ions such as oxalate ion $\left({{{\mathbf{C}}_{\mathbf{2}}}{\mathbf{O}}_{\mathbf{4}}^{{\mathbf{2-}}}}\right)$, hydroxide ion $\left({{\mathbf{O}}{{\mathbf{H}}^{\mathbf{-}}}}\right)$, phosphate ion $\left({{\mathbf{PO}}_{\mathbf{4}}^{{\mathbf{3-}}}}\right)$ that can form a precipitate with ${\mathbf{C}}{{\mathbf{a}}^{{\mathbf{2+}}}}$ ions.

Learn more:

1. Identify the precipitate in the reaction: brainly.com/question/8896163

2. The main purpose of conducting experiments: brainly.com/question/5096428

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Chemical reaction and equation

Keywords: precipitate, soluble, insoluble, solubility rules, solubility, precipitation reaction, Ca2+. anion, carbonate, sulfates, SO42-, CO32-, CaSO4, CaCO3, hydroxide, OH-, oxalate, C2O42-, phosphate, PO43-.

Answer 2

Answer is: sulfate anion.

Balanced chemical reaction: Ca²⁺(aq) + SO₄²⁻(aq) → CaSO₄(s) .

Calcium sulfate (CaSO₄) has very low solubility in water (Ksp for calcium sulfate is 2.36·10⁻⁴).

Calcium cation (Ca²⁺) will form a precipitate with other anions also:

1) with oxalate anion (C₂O₄²⁻) will form CaC₂O₄(s), calcium oxalate.

2) with phosphate anion (PO₄³⁻) will form Ca₃(PO₄)₂(s), calcium phosphate.

3) with hydroxide anion (OH⁻) will form Ca(OH)₂(s), calcium hydroxide.

4) with carbonate (CO₃²⁻) will form CaCO₃(s), calcium carbonate.