sodium hydroxide: meaning, definition, pronunciation and examples

Low-frequency outside technical/chemical contexts
UK/ˌsəʊ.di.əm haɪˈdrɒk.saɪd/US/ˌsoʊ.di.əm haɪˈdrɑːk.saɪd/

Technical/Scientific

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Quick answer

What does “sodium hydroxide” mean?

A strongly alkaline chemical compound with the formula NaOH, commonly known as caustic soda or lye.

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Pronunciation

Definition

Meaning and Definition

A strongly alkaline chemical compound with the formula NaOH, commonly known as caustic soda or lye.

A white solid ionic compound used extensively in industry and laboratories as a strong base, reagent, pH regulator, and cleaning agent.

Dialectal Variation

British vs American Usage

Differences

No major lexical differences; both use 'sodium hydroxide' as the standard chemical term. In domestic contexts, 'caustic soda' is equally common in both varieties; 'lye' is somewhat more frequent in American English for soap-making contexts.

Connotations

Neutral technical term in both varieties; carries strong connotations of hazard and corrosiveness.

Frequency

Equally low in general discourse, equally high in scientific/industrial discourse.

Grammar

How to Use “sodium hydroxide” in a Sentence

[substance] + reacts with + sodium hydroxidesodium hydroxide + is used to + [base action]add + sodium hydroxide + to + [substance]dissolve + [substance] + in + sodium hydroxide

Vocabulary

Collocations

strong
concentrated sodium hydroxideaqueous sodium hydroxidesodium hydroxide solutionsolid sodium hydroxidesodium hydroxide pellets
medium
react with sodium hydroxidedissolve in sodium hydroxidetreat with sodium hydroxideprecipitate with sodium hydroxide
weak
handle sodium hydroxidestore sodium hydroxidebuy sodium hydroxidedangerous sodium hydroxide

Examples

Examples of “sodium hydroxide” in a Sentence

verb

British English

  • The mixture was sodium-hydroxided to adjust the pH.
  • (Note: very rare/non-standard; standard phrasing: 'treated with sodium hydroxide')

American English

  • They sodium-hydroxided the solution before testing.
  • (Note: very rare/non-standard)

adjective

British English

  • A sodium-hydroxide solution was prepared.
  • The sodium-hydroxide concentration was critical.

American English

  • The sodium-hydroxide treatment was effective.
  • Follow sodium-hydroxide safety protocols.

Usage

Meaning in Context

Business

Referenced in chemical supply, manufacturing (soap, paper, textiles), and safety data sheets.

Academic

Common in chemistry textbooks, lab manuals, and research papers discussing bases, saponification, or neutralization reactions.

Everyday

Rare; might appear in DIY cleaning or soap-making instructions as 'caustic soda'.

Technical

Precise term in chemical engineering, industrial processes, laboratory protocols, and hazard communication.

Vocabulary

Synonyms of “sodium hydroxide”

Strong

NaOH (chemical formula)lye (in specific contexts)

Weak

strong basealkali

Vocabulary

Antonyms of “sodium hydroxide”

Watch out

Common Mistakes When Using “sodium hydroxide”

  • Pronouncing 'hydroxide' with stress on first syllable (/ˈhaɪ.drɒk.saɪd/) instead of second (/haɪˈdrɒk.saɪd/).
  • Using 'sodium hydrate' (archaic/incorrect).
  • Confusing with sodium bicarbonate (baking soda).

FAQ

Frequently Asked Questions

Yes, it is highly corrosive and can cause severe chemical burns. Proper safety equipment (gloves, goggles) is essential when handling it.

Sodium hydroxide (NaOH) is a strong base (caustic soda). Baking soda is sodium bicarbonate (NaHCO₃), a much milder compound used in cooking and as a gentle cleaner.

Yes, in some drain cleaners or oven cleaners, often labelled as 'caustic soda' or 'lye'. Pure forms are sold for soap-making or industrial use.

It reacts with fats or oils in a process called saponification, breaking them down into soap (fatty acid salts) and glycerol.

A strongly alkaline chemical compound with the formula NaOH, commonly known as caustic soda or lye.

Sodium hydroxide is usually technical/scientific in register.

Sodium hydroxide: in British English it is pronounced /ˌsəʊ.di.əm haɪˈdrɒk.saɪd/, and in American English it is pronounced /ˌsoʊ.di.əm haɪˈdrɑːk.saɪd/. Tap the audio buttons above to hear it.

Phrases

Idioms & Phrases

  • None specific to this term

Learning

Memory Aids

Mnemonic

Think 'SODium HydrOXide' – it's a SOap-making, Drain-cleaning OXidizing base.

Conceptual Metaphor

Often conceptualized as a 'chemical scavenger' (for acids) or a 'corrosive cleaner'.

Practice

Quiz

Fill in the gap
In the lab, we carefully added to the beaker to neutralise the acid.
Multiple Choice

What is a common domestic name for sodium hydroxide?