Assertion (A): Compounds are invariably homogeneous.
Reason (R): Compounds are constituted of only one kind of molecule distributed uniformly.
Both A and R are true and R is the correct explanation of A.
Explanation for Assertion statement: When two or more chemical elements are chemically linked together, they form a compound. In any compound, the constituents are always present in specific proportions and thus are homogenous. A homogeneous mixture is one in which the composition is uniform throughout the solution.
Explanation for Reason statement: Compounds have a defined composition and are homogeneous. Chemically, compounds can be broken down into their basic elements. It possesses characteristics that are distinct from those of its constituent pieces.
Conclusion: Hence, option (a) is correct.