# Hydrogen and chlorine react together to form hydrogen chloride gas. Explain why hydrogen chloride is a molecule and describe the type of bonding present in it.

> OCR A-Level Chemistry B: Salters (H433) — 2.1 Atoms, compounds, molecules and equations · Explain · 5 marks

> Hydrogen chloride (HCl) is a gas at room temperature. It is used in industrial processes and forms when hydrogen gas reacts with chlorine gas. Both hydrogen and chlorine are non-metals.

## Mark scheme (5 marks)

1. Hydrogen chloride is a molecule because it contains at least two atoms held together by covalent bonds
2. A covalent bond is a shared pair of electrons
3. Both hydrogen and chlorine are non-metals, so a covalent bond forms between them
4. Each hydrogen atom has one electron in its outer shell and shares it with one electron from chlorine
5. Sharing electrons gives both atoms a full outer electron shell / stable electron arrangement

## Key terms

- [molecule](https://www.gradenine.co.uk/glossary/molecule)

## Related

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Source: [GradeNine](https://www.gradenine.co.uk/q/hydrogen-and-chlorine-react-together-to-2a11793f) · Published by Druglandscape Ltd.