--- title: "Sodium Hydride in Organic Chemistry" description: "Sodium hydride is a strong base and hydride reagent in Organic Chemistry, used to form alkoxides and enolates for ether, Wittig, aldol, and Claisen reactions." canonical: "https://fiveable.me/organic-chem/key-terms/sodium-hydride" type: "key-term" subject: "Organic Chemistry" unit: "Unit 18" --- # Sodium Hydride in Organic Chemistry ## Definition Sodium hydride (NaH) is a strong base in organic chemistry that removes acidic protons to form alkoxides, enolates, or ylides. It is used to drive reactions like ether formation, Wittig reactions, aldol reactions, and Claisen condensations. ## What It Is Sodium hydride, NaH, is a strong base in Organic Chemistry that is usually used to deprotonate, not to add a carbon chain itself. The reactive part is the hydride ion, H-, which grabs an acidic proton from an alcohol, carbonyl compound, or phosphonium salt and leaves behind a more useful reactive intermediate. That intermediate is often the whole point of using NaH. If you treat an alcohol with sodium hydride, you form an alkoxide ion. If you treat a carbonyl compound with the right acidic alpha hydrogen, you can form an enolate. If you start with a phosphonium salt, NaH can remove a proton and generate the phosphorus ylide needed for a Wittig reaction. A lot of students first think NaH is a nucleophile that attacks carbon the way bromide or cyanide would. That is not how it is usually used in this course. In practice, it is a strong, relatively non-nucleophilic base under the right conditions, so its main job is proton removal. The product of that proton removal is what goes on to do the useful bond-forming step. The reaction conditions matter a lot. NaH is moisture-sensitive and reacts violently with water, so it is handled under anhydrous conditions and often in an aprotic solvent. That matters in synthesis problems because if the solvent or glassware contains water, the base gets consumed before it can make the alkoxide, enolate, or ylide you need. You will see sodium hydride in multi-step mechanisms where one small deprotonation changes the whole pathway. In a Williamson ether synthesis, for example, NaH converts an alcohol into an alkoxide, and that alkoxide can then do an SN2 attack on a suitable alkyl halide. In carbonyl chemistry, the same base can generate an enolate for mixed aldol or mixed Claisen chemistry, where control over which partner is deprotonated is the main challenge. ## Why It Matters Sodium hydride shows up whenever a reaction depends on making a stronger nucleophile from a weaker one. In Organic Chemistry, that usually means turning an alcohol into an alkoxide, a carbonyl compound into an enolate, or a phosphonium salt into a phosphorus ylide. Once you can spot that step, the rest of the mechanism becomes easier to read because you know what reactive intermediate is about to form. It also helps you predict whether a synthesis will work. If a problem asks for an ether, NaH often signals a Williamson ether synthesis. If you see a carbonyl compound and a base-promoted C-C bond-forming reaction, NaH may be there to generate the enolate. If the target is an alkene from a carbonyl compound, NaH may be the reagent used to form the ylide for a Wittig reaction. The other big reason it matters is selectivity. NaH is strong enough to pull off a proton, but the product depends on which hydrogen is acidic enough and what reactant is present. That lets you trace mechanism steps more carefully instead of memorizing product names only. ## Connections ### [Alkoxide Ion](/organic-chem/key-terms/alkoxide-ion) NaH is commonly used to make an alkoxide ion from an alcohol. Once the alkoxide forms, it can act as a much stronger nucleophile in reactions like Williamson ether synthesis. If you see NaH followed by an alcohol, think deprotonation first, then substitution or another nucleophilic step. ### [Aprotic Solvent](/organic-chem/key-terms/aprotic-solvent) NaH works best when the solvent does not donate protons back to it. An aprotic solvent helps keep the base active and prevents it from being wasted by acid-base side reactions. On mechanism questions, solvent choice can tell you whether NaH is meant to survive long enough to form an enolate or alkoxide. ### Nucleophile NaH itself is usually discussed as a base, but the species it helps create is often the real nucleophile. The alkoxide or enolate formed after deprotonation is what attacks the electrophile. That distinction matters when you are deciding which step is acid-base and which step is bond formation. ### [Ambident Nucleophiles](/organic-chem/key-terms/ambident-nucleophiles) When NaH forms an enolate, that enolate may react through more than one atom. Ambident nucleophiles can attack through carbon or oxygen depending on the substrate and conditions. This comes up in carbonyl chemistry problems where you have to predict which site of the enolate will react. ## On the AP Exam A quiz or problem-set question will usually show NaH as a clue that the first step is deprotonation. You may need to identify the intermediate it forms, such as an alkoxide in ether synthesis, an enolate in aldol or Claisen chemistry, or a phosphorus ylide in a Wittig reaction. The move is to trace the proton transfer before you worry about the final product. If the question includes water, alcohol, or another protic solvent, check whether NaH would be quenched. If the setup is dry and aprotic, NaH is probably there to build a reactive anion. Then you can follow that anion into SN2 attack, carbonyl addition, or alkene formation depending on the rest of the reagents. ## Sodium Hydride vs Sodium metal Sodium hydride and sodium metal are both used to make alkoxides, but they are not the same reagent. Sodium hydride gives you direct deprotonation with H- as the basic species, while sodium metal works by a different electron-transfer process. In mechanism questions, NaH usually signals a clean acid-base step, not a metal reduction. ## Key Takeaways - Sodium hydride is a strong base in Organic Chemistry, and its main job is to remove a proton so a more reactive intermediate can form. - When NaH reacts with an alcohol, it forms an alkoxide ion, which can then do SN2 substitution in ether synthesis. - When NaH removes an alpha proton from a carbonyl compound, it forms an enolate that can react in aldol or Claisen chemistry. - In the Wittig reaction, NaH can help generate the phosphorus ylide that later turns a carbonyl compound into an alkene. - Because NaH reacts with water, it is used under anhydrous conditions and in dry solvents. ## FAQs ### What is sodium hydride in Organic Chemistry? Sodium hydride, NaH, is a strong base used to remove acidic protons and form reactive anions like alkoxides, enolates, and ylides. It is not mainly used to add across a double bond. Instead, it sets up the intermediate that does the next bond-forming step. ### Is sodium hydride a nucleophile or a base? In most organic reactions, NaH is treated as a base first. Its hydride ion removes a proton, and the resulting alkoxide, enolate, or ylide becomes the species that reacts further. That is why NaH is more often linked to deprotonation than direct carbon attack. ### What does sodium hydride do in ether synthesis? NaH deprotonates an alcohol to form an alkoxide ion. The alkoxide then attacks an alkyl halide in an SN2 reaction to make an ether. If the substrate is too crowded or the conditions are wet, the reaction usually fails or becomes messy. ### Why is sodium hydride used under anhydrous conditions? NaH reacts strongly with water, so moisture can destroy the reagent before it does the desired deprotonation. Dry glassware and aprotic solvents help keep the base available for forming alkoxides, enolates, or ylides. This is a common detail in synthesis and mechanism problems. ## Related Study Guides - [18.2 Preparing Ethers](/organic-chem/unit-18/preparing-ethers/study-guide/3u7GZmbiWcwrO1FM) - [23.5 Mixed Aldol Reactions](/organic-chem/unit-23/mixed-aldol-reactions/study-guide/R3xegSwF4znGuErS) - [23.8 Mixed Claisen Condensations](/organic-chem/unit-23/mixed-claisen-condensations/study-guide/e573kGHCQIjuxxON) - [19.11 Nucleophilic Addition of Phosphorus Ylides: The Wittig Reaction](/organic-chem/unit-19/nucleophilic-addition-phosphorus-ylides-wittig-reaction/study-guide/pph4tD2Ck0sWNewl) ## About This Document Canonical Fiveable pages are available as Markdown at the same path plus `.md`. - [llms.txt](https://fiveable.me/llms.txt): index of Fiveable's sections and URL patterns - [llms-full.txt](https://fiveable.me/llms-full.txt): complete subject and unit listing - [MCP server](https://fiveable.me/mcp): call Fiveable as tools instead of fetching pages (`https://fiveable.me/api/mcp`) - [MCP server for AP teachers](https://fiveable.me/mcp/teachers): a teacher's classes, assignments and AP-rubric grading (`https://fiveable.me/api/mcp/teacher`) ## Structured Data ```json {"@context":"https://schema.org","@graph":[{"@type":"LearningResource","@id":"https://fiveable.me/organic-chem/key-terms/sodium-hydride#resource","name":"Sodium Hydride in Organic Chemistry","url":"https://fiveable.me/organic-chem/key-terms/sodium-hydride","learningResourceType":"Concept explainer","educationalLevel":"AP® / High School","about":{"@id":"https://fiveable.me/organic-chem/key-terms/sodium-hydride#term"},"audience":{"@type":"EducationalAudience","educationalRole":"student"},"dateModified":"2026-07-03T02:23:42.322Z","isPartOf":{"@type":"Collection","name":"Organic Chemistry Key Terms","url":"https://fiveable.me/organic-chem/key-terms"},"author":{"@type":"Organization","@id":"https://fiveable.me/editorial#content-team","name":"Fiveable Content Team","url":"https://fiveable.me/editorial","parentOrganization":{"@id":"https://fiveable.me/#organization"},"member":[{"@type":"Person","name":"Amanda DoAmaral","sameAs":["https://www.linkedin.com/in/adoamaral"]},{"@type":"Person","name":"Becky Bahr","sameAs":["https://www.linkedin.com/in/becky-bahr-b52743132"]}]},"publisher":{"@type":"Organization","name":"Fiveable","url":"https://fiveable.me"}},{"@type":"DefinedTerm","@id":"https://fiveable.me/organic-chem/key-terms/sodium-hydride#term","name":"Sodium Hydride","description":"Sodium hydride (NaH) is a strong base in organic chemistry that removes acidic protons to form alkoxides, enolates, or ylides. 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