Final answer:
The compound that does not contain a polyatomic ion is hydrogen cyanide (HCN). It is composed of individual atoms of hydrogen, carbon, and nitrogen, with no polyatomic ions.
Step-by-step explanation:
The question is asking which compound does not contain a polyatomic ion. A polyatomic ion is a charged group of covalently bonded atoms that function as a single ion. From the options given:
- Option 1: H2SO - Presumably a typo for H2SO4 (sulfuric acid), which contains the polyatomic sulfate ion (SO42-).
- Option 2: HCN - Hydrogen cyanide, composed entirely of single atoms bonded together (H, C, and N), and not containing any polyatomic ions.
- Option 3: NaOH - Sodium hydroxide, which contains the polyatomic hydroxide ion (OH-).
- Option 4: H2S - Hydrogen sulfide, like HCN, is made of only hydrogen and sulfur atoms bonded directly and does not include a polyatomic ion.
Therefore, HCN and H2S do not contain polyatomic ions. However, as we are to choose one that does not contain polyatomic ions, the correct answer is Option 2: HCN.