Sodium hydroxide CAS 1310-73-2

Sodium hydroxide (CAS 1310-73-2, formula HNaO) is an industrial chemical with a molecular weight of about 40 g/mol. Its harmonised GHS classification carries the signal word Danger.

Identifiers

Name

Sodium hydroxide

CAS number

1310-73-2

CLP index number

011-002-00-6

EC number

688-015-4

Molecular formula

HNaO

Molecular weight

40 g/mol

Also known as

Caustic soda, Sodium hydrate, Lye, NaOH, Soda lye, Caustic soda flakes

GHS classification

Harmonised classification under the CLP Regulation (Annex VI), index number 011-002-00-6. Signal word: Danger.

Pictograms

• GHS05 Corrosion

Suppliers may classify additional hazards from their own data, so a supplier's Safety Data Sheet can list more than the harmonised entry.

Source: Regulation (EC) No 1272/2008, Annex VI, retrieved 2026-10-10. Confirm against the current consolidated text and your supplier's SDS before relying on it.

Creating a Safety Data Sheet for a product containing Sodium hydroxide

If Sodium hydroxide is an ingredient, record its CAS number and concentration in Section 3 and use it in the mixture classification that drives Section 2 and the label.

How to write a Safety Data Sheet · GHS mixture classification

Frequently asked questions

What is the CAS number of Sodium hydroxide?

The CAS Registry Number of Sodium hydroxide is 1310-73-2.

What is the chemical formula of Sodium hydroxide?

Sodium hydroxide has the formula HNaO and a molecular weight of about 40 g/mol.

What are the GHS hazards of Sodium hydroxide?

Sodium hydroxide carries the signal word Danger. Its harmonised hazard statements are H314: Causes severe skin burns and eye damage..

Which GHS pictograms apply to Sodium hydroxide?

GHS05 (Corrosion).

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Information is provided for general reference and is not a substitute for a supplier's Safety Data Sheet or professional advice. See our disclaimer.