What is the common name for Mg(OH)2?

What is the common name for Mg(OH)2?

• A. Magnesium hydroxide
• B. Magnesium oxide
• C. Magnesium dihydroxide
• D. Magnesium oxyhydroxide

Answer: (A)

When naming a simple metal hydroxide, the common approach is to put the metal name first and add hydroxide. Mg(OH)2 contains one magnesium ion and two hydroxide ions, so the straightforward, widely used name is magnesium hydroxide. Magnesium oxide would be MgO and contains oxide, not hydroxide. Magnesium dihydroxide is a less common, more formal way some systems might name the compound, but it isn’t the everyday name you’ll see most often. Magnesium oxyhydroxide would imply a structure with both oxide and hydroxide groups in a different arrangement, not this formula. This compound is a base used in products like milk of magnesia and as an antacid; it’s sparingly soluble in water, but the presence of hydroxide ions is what gives it basic properties.

When naming a simple metal hydroxide, the common approach is to put the metal name first and add hydroxide. Mg(OH)2 contains one magnesium ion and two hydroxide ions, so the straightforward, widely used name is magnesium hydroxide.

Magnesium oxide would be MgO and contains oxide, not hydroxide. Magnesium dihydroxide is a less common, more formal way some systems might name the compound, but it isn’t the everyday name you’ll see most often. Magnesium oxyhydroxide would imply a structure with both oxide and hydroxide groups in a different arrangement, not this formula.

This compound is a base used in products like milk of magnesia and as an antacid; it’s sparingly soluble in water, but the presence of hydroxide ions is what gives it basic properties.