This page in your language

فارسی

العربية

Deutsch

Español

Français

日本語

한국어

Português

中文

हिन्दी

B1 adjective 6 min read

acide

Practice it Examples Notes & Tips acide in 30 Seconds

Explanation acide in your Level:

At the A1 level, you only need to know 'acide' as a basic descriptive word for food. You will mostly use it to say that a fruit or a drink tastes sharp, like a lemon. You should remember that it doesn't change between 'he' and 'she' forms. For example: 'Le citron est acide' (The lemon is acidic) and 'La pomme est acide' (The apple is acidic). It is a simple adjective to add to your vocabulary for grocery shopping or eating at a restaurant. Focus on the taste aspect for now. You might also see it in the context of 'pluie acide' (acid rain) in very basic environmental posters, but the culinary use is most important for you.

At A2, you can start using 'acide' to describe more complex flavors and simple physical sensations. You might use it to describe a vinaigrette or a yogurt. You should also be aware of the plural form, 'acides', which sounds exactly like the singular. You might encounter it in health contexts, like describing a stomach ache or 'acidité'. You are beginning to move beyond just 'lemon' and can use it to describe a variety of foods that aren't necessarily 'bad' but just have that specific sharp quality. You can also start to recognize it in weather reports or simple science texts about the environment.

At the B1 level, you should be comfortable using 'acide' in both its literal and figurative senses. You can describe a person's tone as 'un ton acide' when they are being sarcastic or biting. This is a common way to describe dialogue in novels or social situations. You should also understand its use in more technical but common domains like 'reflux acide' or 'produits acides'. You should be able to distinguish between 'acide' and 'amer' (bitter) and use the correct one in a restaurant or kitchen. You can also use it to describe colors that are very bright and 'sharp' to the eye, like 'vert acide'.

At B2, you are expected to use 'acide' with more nuance. You might use it in a debate to characterize an opponent's argument as 'une critique acide'. You understand the difference between 'acide' and more literary synonyms like 'acerbe' or 'mordant'. You can discuss environmental issues like 'l'acidification des océans' using the word family. You are also capable of using it in professional contexts, such as describing the chemical properties of a product in a safety manual or the flavor profile of a professional wine tasting. Your use of the word should feel natural in both formal and informal settings.

At the C1 level, 'acide' becomes a tool for precise expression. You use it to describe subtle shades of meaning in literature or high-level journalism. You might analyze a writer's 'style acide' and how it serves their satirical purpose. You are aware of idiomatic expressions and can use them flawlessly. You understand the historical and etymological roots, which helps you grasp why it is used in certain legal or historical texts (e.g., 'un différend acide'). You can switch between 'acide', 'acidulé', and 'caustique' to provide the exact level of intensity and connotation required for your specific context.

At the C2 level, you have a total mastery of 'acide'. You can use it in highly specialized fields, from advanced chemistry to philosophical treatises on 'l'acidité de la condition humaine'. You recognize its use in archaic or very formal French where it might appear in older legal documents. You can play with the word in creative writing, using it to create vivid imagery or metaphors that go beyond the standard 'sour' or 'sarcastic'. You are also fully aware of its register—knowing when it sounds like a common observation and when it sounds like a sharp, intellectual jab. You can even explain the nuances of the word to others.

Practice it Examples Notes & Tips

acide in 30 Seconds

Primarily means 'acidic' or 'sour' in a culinary or chemical context.
Used figuratively to describe sharp, biting, or sarcastic speech and personality.
Remains 'acide' for both masculine and feminine singular; adds 's' for plural.
Common in science (pH), environment (acid rain), and daily life (citrus fruits).

The French word acide is a versatile adjective that functions much like its English cognate. At its most literal level, it describes a sensory experience—specifically, the sharp, sour taste associated with citrus fruits, vinegar, or fermented products. In the culinary world, it is the opposite of sucré (sweet) or doux (mild). However, its utility extends far beyond the kitchen. In a scientific context, acide refers to substances with a pH lower than 7, such as l'acide sulfurique. This technical usage is fundamental in chemistry and biology. Beyond the physical, the word takes on a powerful figurative meaning. When describing a person's tone, remarks, or personality, it suggests something biting, sarcastic, or caustic. An esprit acide is one that is sharp-witted but perhaps unkind. This transition from literal sourness to metaphorical bitterness is a common linguistic bridge in both French and English, making it an intuitive but essential word for B1 learners to master.

Culinary Context: Used to describe the sharp tang of lemons, unripe grapes, or a vinaigrette that has too much vinegar.

Cette pomme verte est encore trop acide pour être mangée.

Chemical Property: Refers to the pH balance and chemical reactivity of substances in a laboratory or environmental setting.

Les pluies acides endommagent les forêts boréales.

Figurative Usage: Describes speech or writing that is sharp, critical, or intended to sting the recipient.

Elle a répondu d'un ton acide qui a mis fin à la discussion.

In everyday French life, you will encounter this word frequently when discussing health (gastric acidity), environment (acid rain), or even art (acid colors). It is a high-frequency word because it bridges the gap between the physical senses and abstract social interactions. Understanding the nuance between 'acide' (sour/acidic) and 'amer' (bitter) is a key milestone for intermediate learners, as 'acide' often carries a more aggressive or piercing connotation than 'amer'.

Using acide correctly requires attention to its placement and the noun it modifies. In French, most adjectives follow the noun, and acide is no exception. Whether you are talking about un fruit acide or une solution acide, the adjective typically trails the noun to provide specific classification. However, when used figuratively, it can sometimes precede the noun for stylistic emphasis in literary contexts, though this is rare in spoken French. One of the most common structures involves the verb être (to be), as in Ce vin est trop acide. This is the simplest way to describe a state or quality. For B1 learners, it is also important to practice the plural form: des critiques acides. Notice that the pronunciation does not change with the addition of the 's'.

L'estomac produit des sucs acides pour la digestion.

When you want to modify the intensity of the acidity, you can use adverbs like très (very), un peu (a bit), or extrêmement (extremely). For example, Le goût est légèrement acide. In professional settings, particularly in wine tasting (œnologie), the term is used with precision. A wine might be described as having a 'belle acidité' (good acidity), where the noun form is preferred over the adjective to describe structure. In contrast, calling a wine simply acide often implies a defect, suggesting it is out of balance or too sharp.

Il a un humour acide que tout le monde n'apprécie pas.

You will hear acide in several distinct environments in France. First, in the supermarket or kitchen. If you are buying fruit and ask the vendor about the taste of a particular plum, they might say, 'Elle est un peu acide, c'est une variété tardive.' Second, in medical or health conversations. French people are quite conscious of their digestion, and you might hear someone complain about 'remontées acides' (acid reflux) after a heavy meal. Third, in the news and media. Journalists often use the term to describe political commentary or a 'critique acide' of a new film or government policy. This figurative use is very common in high-level debate and editorial writing.

Le présentateur a fait un commentaire acide sur la situation actuelle.

In the world of fashion and design, 'couleurs acides' refers to bright, neon, or 'electric' colors like lime green or hot pink—colors that 'sting' the eyes much like acid stings the tongue. This usage is particularly common in spring/summer collection reviews. Finally, in music, specifically electronic music, you will hear about 'Acid House', which is a direct loan from English but is discussed in French with the same descriptive intent regarding its sharp, repetitive synthesizer sounds.

The most frequent mistake for English speakers is confusing acide with amer (bitter) or aigre (sour/tart). While they are related, they are not interchangeable. Acide is the broad category for things like lemons. Amer is for things like dark chocolate, coffee, or chicory. If you call a lemon 'amer', a French speaker will be confused. Aigre usually implies a fermented or spoiled sourness, like sour milk (lait aigre) or sauerkraut (choucroute). Another mistake is grammatical: adding an 'e' to make it feminine. Remember, acide is already feminine-ready! Writing acidée is a common error; that is not a word. Lastly, avoid using 'acide' to mean 'mean' or 'angry' in a general sense. While it can mean sarcastic, it doesn't translate to 'He is being acid' if you just mean he is in a bad mood.

Acide vs. Amer: Acide = Lemon/Vinegar. Amer = Coffee/Radicchio.

Acide vs. Aigre: Acide is often a natural quality; Aigre often implies fermentation or spoilage.

If acide feels too generic, French offers several alternatives depending on the nuance you want to convey. For food that is pleasantly tart, you might use acidulé. This suggests a candy-like or refreshing sourness, often found in sweets or light white wines. If you are describing someone's sharp tongue, acerbe is a more sophisticated, literary synonym. It suggests a critique that is not only sharp but intended to hurt or diminish. For things that are physically corrosive, caustique is used, both in chemistry and figuratively for humor. If something is just slightly sour, aigrelet is a charming, diminutive form often used in literature to describe wild berries or a small voice.

Comparison Table

Acide: General term (Lemon, pH).
Acidulé: Pleasant, tangy (Candy, fruit).
Acerbe: Harsh, biting (Criticism).
Aigre: Sour, often unpleasant (Spoiled food).

How Formal Is It?

Formal

Neutral

Informal

Child friendly

Slang

Fun Fact

The word 'acid' in English comes from the same Latin root. In the 17th century, it began to be used more formally in chemistry to describe substances that react with metals.

Pronunciation Guide

UK /a.sid/

US /a.sid/

In French, stress is usually on the last syllable: a-SIDE.

Rhymes With

lucide vide rapide humide solide liquide timide rigide

Common Errors

Pronouncing it like the English word 'acid' (with a short 'i').
Adding a 'd' sound at the end like 'acided'.
Over-emphasizing the 'e' at the end; it should be almost silent.
Confusing the 'a' sound with 'o'.
Missing the 's' sound in the middle (don't say 'a-ide').

Difficulty Rating

Reading 2/5

Easy to recognize due to the English cognate.

Writing 3/5

Easy to spell, but remember it doesn't change for gender.

Speaking 2/5

Simple pronunciation, just watch the 'seed' sound.

Listening 2/5

Clear sound, but don't confuse with 'assise' or 'acide' (noun).

What to Learn Next

Prerequisites

le goût le citron manger boire très

Learn Next

amer sucré salé acerbe caustique

Advanced

l'alcalinité la corrosion le sarcasme l'œnologie la biochimie

Grammar to Know

Adjective agreement with 'e' endings

Un homme acide, une femme acide.

Adjective placement (usually after the noun)

Un liquide acide.

Comparative of adjectives

Le citron est plus acide que l'orange.

Adverbs of intensity

C'est extrêmement acide.

Pluralization of adjectives

Des critiques acides.

Examples by Level

Le citron est acide.

The lemon is acidic.

Simple subject-verb-adjective structure.

J'aime les bonbons acides.

I like sour candies.

Plural adjective follows the noun.

Cette orange n'est pas acide.

This orange is not acidic.

Negation with 'ne...pas'.

Le vinaigre est très acide.

Vinegar is very acidic.

Use of 'très' to modify intensity.

La pomme verte est acide.

The green apple is acidic.

Adjective agreement with feminine singular noun.

C'est un goût acide.

It is an acidic taste.

Masculine singular noun 'goût'.

Les fruits sont acides.

The fruits are acidic.

Plural agreement with 'fruits'.

Est-ce que c'est acide ?

Is it acidic?

Question structure with 'est-ce que'.

Cette sauce est un peu trop acide.

This sauce is a little too acidic.

Use of 'un peu trop' for nuance.

Le yaourt nature est parfois acide.

Plain yogurt is sometimes acidic.

Adverb 'parfois' adds frequency.

Il ne faut pas boire de liquides acides.

You must not drink acidic liquids.

Negative imperative with plural adjective.

Ma gorge est irritée par l'acidité.

My throat is irritated by the acidity.

Noun form 'acidité' introduced.

Les citrons verts sont plus acides que les citrons jaunes.

Limes are more acidic than lemons.

Comparative structure 'plus...que'.

Ce vin blanc a un côté acide.

This white wine has an acidic side.

Using 'un côté' to describe a trait.

Attention, ce produit est acide.

Watch out, this product is acidic.

Warning context.

Le sol de mon jardin est acide.

The soil in my garden is acidic.

Environmental/Gardening context.

Il m'a répondu d'un ton acide.

He answered me in an acidic tone.

Figurative use for personality/tone.

Les pluies acides sont un problème écologique.

Acid rain is an ecological problem.

Set phrase 'pluies acides'.

Elle a fait une remarque acide sur ma tenue.

She made an acidic remark about my outfit.

Figurative use for social interaction.

Le pH indique si une solution est acide ou basique.

The pH indicates if a solution is acidic or basic.

Technical/Scientific context.

J'évite les aliments trop acides pour mon estomac.

I avoid foods that are too acidic for my stomach.

Health/Dietary context.

Son humour acide ne plaît pas à tout le monde.

His acidic humor doesn't please everyone.

Describing a type of humor.

La batterie contient un liquide acide et dangereux.

The battery contains an acidic and dangerous liquid.

Descriptive adjectives in a sequence.

Le raisin n'est pas encore mûr, il est très acide.

The grape is not yet ripe, it is very acidic.

Cause and effect relationship.

Le critique a publié un article acide sur le nouveau film.

The critic published an acidic article about the new film.

Professional figurative use.

L'acidification des océans menace les récifs coralliens.

Ocean acidification threatens coral reefs.

Related noun 'acidification'.

Elle possède un esprit vif et parfois un peu acide.

She has a sharp and sometimes slightly acidic mind.

Describing intellectual character.

Ce fromage a une pointe d'acidité très agréable.

This cheese has a very pleasant hint of acidity.

Positive culinary nuance.

Le ton de la discussion est devenu brusquement acide.

The tone of the discussion suddenly became acidic.

Describing a change in atmosphere.

Il faut neutraliser ce mélange acide avec une base.

This acidic mixture must be neutralized with a base.

Chemical process description.

Les couleurs acides de ce tableau sont frappantes.

The acidic colors of this painting are striking.

Artistic context (neon colors).

Sa réaction acide a surpris toute l'assemblée.

His acidic reaction surprised the whole assembly.

Social impact description.

L'auteur manie une plume acide pour dénoncer l'injustice.

The author wields an acidic pen to denounce injustice.

Metaphorical 'plume acide' (writing style).

Le conflit s'est envenimé par des échanges acides.

The conflict worsened through acidic exchanges.

Describing a deteriorating relationship.

Une trop grande acidité gastrique peut causer des ulcères.

Too much gastric acidity can cause ulcers.

Formal medical terminology.

Son regard acide traduisait un profond mépris.

His acidic look conveyed deep contempt.

Describing non-verbal communication.

L'équilibre acide-base est crucial pour l'organisme.

The acid-base balance is crucial for the organism.

Compound adjective 'acide-base'.

La satire était si acide qu'elle fut censurée.

The satire was so acidic that it was censored.

Describing political/literary impact.

Ces remarques acides ne font qu'aggraver la situation.

These acidic remarks only make the situation worse.

Describing counter-productive behavior.

Il a une vision acide du monde qui l'entoure.

He has an acidic vision of the world around him.

Describing a worldview.

L'âcreté de son discours se mêlait à une ironie acide.

The bitterness of his speech mingled with an acidic irony.

High-level literary description.

L'acide désoxyribonucléique est le support de l'hérédité.

Deoxyribonucleic acid is the carrier of heredity.

Full scientific name for DNA.

Elle fustigeait ses contemporains d'un verbe acide.

She castigated her contemporaries with acidic words.

Archaic/Literary 'verbe'.

La décomposition produit des vapeurs acides délétères.

Decomposition produces harmful acidic vapors.

Advanced scientific/environmental description.

L'acidité de cette œuvre picturale déconcerte le public.

The acidity of this pictorial work disconcerts the public.

Abstract art criticism.

Un tempérament acide peut masquer une grande souffrance.

An acidic temperament can mask great suffering.

Psychological depth.

Les relents acides de la cave témoignaient de l'humidité.

The acidic smells of the cellar testified to the humidity.

Sensory literary description.

Il maniait l'insulte acide avec une précision chirurgicale.

He wielded acidic insults with surgical precision.

Metaphorical use of 'chirurgicale'.

Common Collocations

Pluie acide

Goût acide

Ton acide

Solution acide

Reflux acide

Remarque acide

Couleur acide

Acide aminé

Acide gras

Critique acide

Common Phrases

Avoir un ton acide

— To speak in a sharp, biting, or sarcastic manner.

Pourquoi as-tu ce ton acide ce matin ?

Être acide comme un citron

— To be extremely sour or very sharp-tongued.

Cette pomme est acide comme un citron.

Un mélange acide

— A combination of substances or ideas that is sharp or volatile.

C'est un mélange acide de politique et de religion.

L'acidité gastrique

— Stomach acid or heartburn issues.

L'acidité gastrique m'empêche de dormir.

Des propos acides

— Words or comments that are meant to hurt or sting.

Ses propos acides ont choqué ses amis.

Un regard acide

— A look full of judgment or dislike.

Il m'a jeté un regard acide avant de partir.

Une réaction acide

— A chemical reaction or a sharp social response.

La réaction acide a produit du gaz.

Un fruit acide

— A fruit that is not sweet, but sharp.

Le pamplemousse est un fruit acide.

Un humour acide

— A type of dark, biting, or sarcastic humor.

J'adore son humour acide, c'est très drôle.

Un environnement acide

— A place with acidic conditions (soil, water, or atmosphere).

Certaines plantes aiment les environnements acides.

Often Confused With

acide vs amer

Amer means bitter (like coffee), while acide means sour (like lemon).

acide vs aigre

Aigre implies something that has turned sour or spoiled, like milk.

acide vs âcre

Âcre describes a harsh, irritating smell or taste that burns the throat.

Idioms & Expressions

"Avoir la dent acide"

— To be very critical or prone to making biting remarks.

Fais attention, elle a la dent acide aujourd'hui.

informal

"Une plume acide"

— A sharp, critical writing style.

Ce journaliste est connu pour sa plume acide.

formal

"S'en mordre les doigts (contexte acide)"

— While not using the word, 'acide' situations often lead to this: to regret something bitterly.

Il a fait une remarque acide et s'en mord les doigts.

neutral

"Laver à l'acide"

— To clean thoroughly or, figuratively, to purge or criticize severely.

Le patron a lavé le projet à l'acide.

metaphorical

"Tomber dans l'acide"

— To enter a very harsh or toxic situation.

Leur relation est tombée dans l'acide.

figurative

"Un sourire acide"

— A smile that is forced or mocking.

Elle m'a adressé un sourire acide.

neutral

"C'est de l'acide"

— Used to describe something very painful or destructive.

Ses paroles, c'est de l'acide pour mon cœur.

poetic

"Un ton de vinaigre (similaire à acide)"

— A sour, unpleasant tone of voice.

Elle parle toujours avec un ton de vinaigre.

informal

"L'acide du temps"

— The destructive power of time passing.

Rien ne résiste à l'acide du temps.

literary

"Brûler comme de l'acide"

— To cause intense emotional or physical pain.

Sa trahison me brûle comme de l'acide.

dramatic

Easily Confused

acide vs Assise

Similar sound.

Assise means 'seated' or 'foundation'.

Elle est assise sur la chaise.

acide vs Acide (noun)

Same spelling.

The noun refers to the substance itself (e.g., LSD or a chemical).

L'acide a brûlé le papier.

acide vs Acide (adjective)

Same spelling.

The adjective describes a quality.

Un fruit acide.

acide vs Acide gras

Technical term.

Refers specifically to fatty acids in nutrition.

Le poisson contient des acides gras.

acide vs Acidulé

Similar meaning.

Acidulé is usually positive and means 'tangy' or 'pleasantly sour'.

Un bonbon acidulé.

Sentence Patterns

Le/La [noun] est acide.

Le citron est acide.

C'est un peu trop acide.

Cette sauce est un peu trop acide.

Il/Elle parle d'un ton acide.

Elle parle d'un ton acide.

J'évite les [nouns] acides.

J'évite les boissons acides.

Une critique acide de [something].

Une critique acide de son livre.

L'acidité de [something] est [adjective].

L'acidité de ce vin est parfaite.

Mier une plume acide contre [something].

Il manie une plume acide contre le gouvernement.

Sous des dehors acides se cache [something].

Sous des dehors acides se cache une grande sensibilité.

Word Family

Nouns

Verbs

Adjectives

How to Use It

frequency

High (Top 2000 words)

Common Mistakes

La pomme est acidée. → La pomme est acide.
There is no word 'acidée'. The adjective is 'acide' for both genders.
Ce café est très acide. → Ce café est très amer.
Coffee is usually bitter (amer), not sour (acide), unless it's a specific flavor profile or spoiled.
Un ton d'acide. → Un ton acide.
You use the adjective directly after the noun, not with 'de'.
Les pluies acide. → Les pluies acides.
Don't forget the 's' for plural agreement.
Il est acide. → Il est désagréable / Il a un ton acide.
Calling a person 'acide' directly is less common than describing their 'ton' or 'esprit' as acide.

Tips

Lemon Link

Always associate 'acide' with a lemon in your mind to remember the primary meaning.

Gender Neutral

Don't add an extra 'e' for feminine nouns. 'Acide' is already perfect as it is!

Tone of Voice

Use 'un ton acide' when writing stories to show a character is being mean or sarcastic.

pH Power

Remember that 'acide' means a pH below 7. This helps in technical translations.

Wine Tasting

In a French wine tasting, use 'acidité' (the noun) to sound like an expert.

Eco-Word

Learn 'pluies acides' to discuss environmental issues in French.

Seed Sound

Think of the English word 'seed' to get the second syllable of 'acide' right.

Sweet vs Sour

Practice 'acide' alongside 'sucré' to master basic taste descriptions.

Biting Prose

Use 'une plume acide' to describe a very critical journalist or author.

Warning Labels

If you see 'acide' on a bottle in France, be careful! It might be corrosive.

Memorize It

Mnemonic

Think of a 'seed' (the sound of the second syllable) of a lemon that is very 'acid'. Ah, a seed is acide!

Visual Association

Imagine a bright yellow lemon with a tiny 'pH' meter sticking out of it showing a low number.

Word Web

Lemon Vinegar Chemistry Sarcasm Biting Stomach Rain pH

Challenge

Try to use 'acide' three times today: once for a food, once for the weather/environment, and once to describe a movie critic's review.

Word Origin

Derived from the Latin 'acidus', meaning 'sour' or 'sharp'. It is related to 'acere' (to be sour) and 'acus' (needle).

Original meaning: Originally referred to the physical sensation of sharpness or sourness on the tongue.

Indo-European > Italic > Latin > French.

Cultural Context

Be careful when calling a person 'acide'; it is a strong critique of their personality.

English speakers use 'acid' similarly, but 'sour' is more common for food. In French, 'acide' covers both 'acidic' and 'sour' (alongside 'aigre').

Les Pluies Acides (environmental movement) Acid House music in the 90s Paris scene L'Acide (a common term in French lab thrillers)

Practice in Real Life

Real-World Contexts

Cooking

Trop acide
Ajouter du sucre
Goût citronné
Vinaigrette acide

Science Class

Le pH est bas
Solution acide
Réaction chimique
Acide sulfurique

Socializing

Un ton acide
Une remarque blessante
Humour noir
Être sarcastique

Health

Brûlures d'estomac
Reflux acide
Aliments à éviter
Médicament anti-acide

Environment

Pluies acides
Pollution atmosphérique
Acidification des sols
Impact écologique

Conversation Starters

"Trouves-tu que ce vin est trop acide ?"

"Aimes-tu les bonbons qui sont très acides ?"

"Est-ce que les pluies acides sont un problème dans ta région ?"

"Pourquoi penses-tu qu'il a répondu d'un ton si acide ?"

"Quels fruits acides préfères-tu manger en été ?"

Journal Prompts

Décrivez un moment où quelqu'un a été acide avec vous. Comment avez-vous réagi ?

Écrivez sur votre plat préféré qui utilise des ingrédients acides comme le citron ou le vinaigre.

Pensez-vous qu'un humour acide est nécessaire dans la comédie moderne ? Pourquoi ?

Quels sont les dangers des pluies acides pour la nature selon vous ?

Racontez une expérience en laboratoire de chimie impliquant une substance acide.

Frequently Asked Questions

10 questions

It is an adjective, so it takes the gender of the noun it modifies. However, since it ends in 'e', the spelling is the same for both masculine and feminine singular (un fruit acide, une pomme acide).

They are very similar. 'Acide' is the direct translation of both 'acidic' and 'sour'. In French, you might also use 'aigre' for 'sour' if the taste is unpleasant or fermented.

Yes, but it describes their temperament or words (sarcastic, biting), not their physical appearance. For example, 'un homme acide' means a man who makes biting remarks.

Yes, it is very common in everyday conversation, science, and literature. It is considered a B1 level word because of its figurative uses.

You say 'pluies acides'. Note that 'pluies' is plural, so 'acides' must also be plural.

The opposite is usually 'sucré' (sweet) or 'doux' (mild).

The opposite is 'basique' (basic) or 'alcalin' (alkaline).

Yes, you add an 's' to make it 'acides'. The pronunciation remains the same.

Yes, 'un acide' is a chemical substance. In slang, it can also refer to the drug LSD.

The best word is 'acidulé', which implies a pleasant, sharp sweetness.