Polyatomic ions, Solubility rules, and Weak Electrolytes

Acetate

C₂H₃O₂⁻

Aluminum

Al³⁺

Ammonium

NH₄⁺

Barium

Ba²⁺

Bicarbonate

HCO₃⁻

Bisulfate

HSO₄⁻

Bisulfide

HS⁻

Bisulfite

HSO₃⁻

Bromate

BrO₃⁻

Bromide

Br⁻ (brown)

Bromite

BrO₂⁻

Calcium

Ca²⁺

Carbonate

CO₃²⁻

Chlorate

ClO₃⁻

Chloride

Cl⁻ (yellow)

Chlorite

ClO₂⁻

Chromate

CrO₄²⁻ (yellow)

Chromium

Cr³⁺

Cupric

Cu²⁺ (blue)

Cuprous

Cu⁺ (blue)

Cyanide

CN⁻

Dichromate

Cr₂O₇²⁻ (orange)

Ferric

Fe³⁺

Ferrious

Fe²⁺

Fluoride

F⁻

Hydrogen

H⁺

Hydronium

H₃O⁺

Hydroxide

OH⁻

Hypobromite

BrO⁻

Hypochlorite

ClO⁻

Hypoiodite

IO⁻

Iodate

IO₃⁻

Iodide

I⁻

Iodite

IO₂⁻

Lead

Pb²⁺

Lithium

Li⁺

Magnesium

Mg²⁺

Manganese

Mn²⁺

Mercuric

Hg²⁺

Mercurous

Hg₂²⁺

Nickel

Ni²⁺ (green)

Nitrate

NO₃⁻

Nitride

N³⁻

Nitrite

NO₂⁻

Oxalate

C₂O₄²⁻

Oxide

O²⁻

Perbromate

BrO₄⁻

Perchlorate

ClO₄⁻

Periodate

IO₄⁻

Permanganate

MnO₄⁻ (purple)

Peroxide

O₂²⁻

Phosphate

PO₄³⁻

Phosphide

P³⁻

Phosphite

PO₃³⁻

Potassium

K⁺

Silver

Ag⁺

Sodium

Na⁺

Stannic

Sn⁴⁺

Stannous

Sn²⁺

Strontium

Sr²⁺

Sulfate

SO₄²⁻

Sulfide

S²⁻

Sulfite

SO₃²⁻

Thiocyanate

SCN⁻

Thiosulfate

S₂O₃²⁻

Zinc

Zn²⁺

8 strong acids (full form)

1. Hydrochloric Acid (HCl)

2. Hydrobromic Acid (HBr)

3. Hydroiodic Acid (Hl)

4. Perchloric Acid (HClO₄)

5. Nitric Acid (HNO₃)

6. Periodic Acid (HIO₄)

7. Sulfuric Acid (H₂SO₄)

8. Chloric Acid (HClO₃)

Weak Acids

1. Ammonium Hydroxide (NH₄OH = NH₃ (aq))

2. Water (H₂O)

Always Soluable

1. alkali metal ions (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺)

2. NH₄⁺ (ammonium)

3. NO₃⁻ (nitrate)

4. ClO₃⁻ (chlorate)

5. ClO₄⁻ (perchlorate)

6. C₂H₃O₂⁻ (acetate)

Generally Soluble

1. Cl⁻, Br⁻, I⁻ → all three are soluble except with Ag⁺, Pb²⁺, and Hg₂²⁺ (AP/H)

2. F⁻ → soluble except with Ca²⁺, Sr²⁺, Ba²⁺, Pb²⁺, and Mg²⁺ (CBS-PM)

3. SO₄²⁻ → soluble except with Ca²⁺, Sr²⁺, Ba²⁺, Pb²⁺ (CBS/PBS)

Generally Insoluble

1. O²⁻ (oxide) and OH⁻ (hydroxide) → insoluble except with alkali metals (six elements in the first group from Lithium - Francium) and NH₄⁺ (ammonium)

2. CO₃²⁻ (carbonate), PO₄³⁻ (phosphate), S²⁻ (sulfide), SO₃²⁻ (sulfite), C₂O₄²⁻ (oxalate), CrO₄²⁻ (chromate) → insoluble except with alkali metals and NH₄⁺

Which ions are somewhat soluble when paired with something that is "generally insoluble"?

Ca²⁺, Sr²⁺, and Ba²⁺ (CBS)

Explanation: When these ions are paired with something that is in the "generally insoluble" list, they do not make the compound fully soluble; instead they make it somewhat soluble (it dissolves a little, but not fully → a cloudy, weak solution). This is because the water molecules can't fully pull them apart, making them only dissolve partially.