Name each ionic compound containing a polyatomic ion. a. Ba(OH)2 b. NH4I c. NaBrO4 d. Fe(OH)3
The correct answer and explanation is:
The ionic compounds containing a polyatomic ion are:
a. Ba(OH)2: Barium hydroxide
b. NH4I: Ammonium iodide
c. NaBrO4: Sodium perbromate
d. Fe(OH)3: Iron(III) hydroxide
Explanation:
- Ba(OH)2: Barium hydroxide is an ionic compound where the cation is Ba²⁺ and the anion is the hydroxide ion (OH⁻), which is a polyatomic ion. The hydroxide ion consists of an oxygen atom bonded to a hydrogen atom, and it carries a negative charge.
- NH4I: Ammonium iodide contains the ammonium ion (NH4⁺), which is a polyatomic ion. The ammonium ion is composed of a nitrogen atom bonded to four hydrogen atoms, carrying a positive charge. The anion in this case is the iodide ion (I⁻), which is a monatomic ion, not a polyatomic ion, but the ammonium ion qualifies this compound as containing a polyatomic ion.
- NaBrO4: Sodium perbromate is composed of the sodium ion (Na⁺) and the perbromate ion (BrO4⁻), which is a polyatomic ion. The perbromate ion contains a bromine atom bonded to four oxygen atoms, carrying a negative charge.
- Fe(OH)3: Iron(III) hydroxide consists of the iron ion (Fe³⁺) and the hydroxide ion (OH⁻). The hydroxide ion is a polyatomic ion, and the compound is often used as a precipitate in chemical reactions.
In summary, a polyatomic ion is an ion made up of two or more atoms that are covalently bonded together, but the entire group carries a charge. In the compounds listed, the hydroxide (OH⁻), ammonium (NH4⁺), and perbromate (BrO4⁻) ions are all polyatomic ions, while the other ions are monatomic (e.g., iodide I⁻, bromide Br⁻).