Final answer:
(3) potassium chloride.The binary compound from the given options is potassium chloride (KCl), which is composed of the elements potassium (K) and chlorine (Cl).
Step-by-step explanation:
A binary compound is a chemical compound that contains exactly two different elements. Examples of binary compounds include sodium chloride (NaCl) and lithium fluoride (LiF), both of which consist of one metal cation and one nonmetal anion.
Based on the choices provided, the compound which is a binary compound is (3) potassium chloride (KCl).
Sodium chlorate (NaClO3), silver nitrate (AgNO3), and ammonium sulfide ((NH4)2S) contain more than two different elements, thus they are not binary compounds.
A binary compound is a compound that is composed of two elements. By looking at the options given, we can determine that potassium chloride is the binary compound.
It is made up of the elements potassium (K) and chlorine (Cl). Sodium chlorate (option 1) is not a binary compound as it contains the polyatomic ion chlorate (ClO3-).
Silver nitrate (option 2) contains the polyatomic ion nitrate (NO3-). Ammonium sulfide (option 4) contains the polyatomic ion sulfide (S2-)