Give each compound an appropriate name or formula.
a) Iron(III) chloride
b) AlBr3
c) Tin(II) acetate
d) Ba(NO3)2 · 2 H2O
e) Phosphoric acid
f) HCN (aq)
g) Chlorous acid
h) HC2H3O2 (aq)
Here are the correct names or formulas for each compound:
a) Iron(III) chloride → FeCl₃
b) AlBr₃ → Aluminum bromide
c) Tin(II) acetate → Sn(C₂H₃O₂)₂
d) Ba(NO₃)₂ · 2 H₂O → Barium nitrate dihydrate
e) Phosphoric acid → H₃PO₄
f) HCN (aq) → Hydrocyanic acid
g) Chlorous acid → HClO₂
h) HC₂H₃O₂ (aq) → Acetic acid
Explanation:
Naming and writing chemical formulas depend on whether a compound is ionic, covalent, or acidic. Transition metals such as iron and tin use Roman numerals to indicate their oxidation states. For example, Iron(III) indicates a +3 charge, requiring three chloride ions (Cl⁻) to balance one Fe³⁺, forming FeCl₃. Similarly, Tin(II) acetate involves a +2 tin ion (Sn²⁺) and two acetate ions (C₂H₃O₂⁻), resulting in Sn(C₂H₃O₂)₂.
For binary ionic compounds like AlBr₃, naming is straightforward: the metal (aluminum) comes first, followed by the nonmetal (bromine) with the suffix “-ide.” No Roman numeral is needed for aluminum because it has only one common charge (+3).
Hydrated salts, like Ba(NO₃)₂ · 2 H₂O, are named by stating the salt followed by a prefix and “hydrate” to indicate the number of water molecules. Hence, the name is barium nitrate dihydrate.
Acids follow different rules. Oxyacids like H₃PO₄ are named based on the polyatomic ion. “Phosphate” becomes “phosphoric acid.” For acids with “-ite” ions, like chlorite (ClO₂⁻), the corresponding acid is named “chlorous acid” (HClO₂). Acids that do not contain oxygen, like HCN, are named using the “hydro-” prefix and “-ic acid” suffix, making hydrocyanic acid. Lastly, HC₂H₃O₂ (aq) is a common weak organic acid known as acetic acid.