Substance with a covalent polar bond: a) H2O; b) K2O; c) Al; d) Cl2.

A covalent polar bond is formed between two different nonmetal atoms.

In example (b), the K2O substance consists of metal and non-metal atoms.

In example (c), aluminum is a metal, it has a metallic bond.

In example (d), the Cl2 molecule consists of two identical nonmetal atoms.

The correct answer is (a), the H2O molecule consists of two different non-metal atoms.

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