Question

The anions that usually form soluble compounds are?

1) Hydroxide ions (OH⁻)
2) Nitrate ions (NO₃⁻)
3) Sulfate ions (SO₄²-)
4) Carbonate ions (CO₃²-)

Answer 1

All four options are anions that usually form soluble compounds:

1. Hydroxide ions (OH⁻)
2. Nitrate ions (NO₃⁻)
3. Sulfate ions (SO₄²-)
4. Carbonate ions (CO₃²-)

What are these anions?

Hydroxide ions (OH⁻): Most hydroxides are soluble, with a few exceptions like magnesium hydroxide and calcium hydroxide.

Nitrate ions (NO₃⁻): Almost all nitrates are readily soluble in water.

Sulfate ions (SO₄²⁻): The majority of sulfate salts are soluble in water. Exceptions include barium sulfate, calcium sulfate, and lead sulfate.

Carbonate ions (CO₃²⁻): Most carbonate salts are soluble, except for those of alkaline earth metals like calcium and magnesium.

Therefore, all four options contribute to forming soluble compounds in most cases.