Final answer:
The compound among the given options is (b) H2O, which is water, composed of hydrogen and oxygen in a 2:1 ratio. So the correcct option is b.
Step-by-step explanation:
The question asks to identify which of the given options is a compound. A compound is a substance formed when two or more chemical elements are chemically bonded together. Out of the given options (a) Cl2, (b) H2O, (c) He, and (d) H2, the correct answer is (b) H2O (water), which consists of hydrogen and oxygen chemically bonded in a ratio of 2:1.
Let's briefly look at the other options:
- (a) Cl2 represents chlorine, which is a diatomic molecule, not a compound, as it consists of two atoms of the same element.
- (c) He stands for helium, which is a noble gas and is not combined with any other element, thus not a compound.
- (d) H2 is molecular hydrogen, another diatomic molecule, consisting of two atoms of the same element, hydrogen.