Difference Between Acids and Alkalis
Acids and alkalis are both corrosive chemical substances used by everyone daily. These substances release Hydrogen ions (H+) when they are mixed/dissolved in water. They taste sour and conduct electricity. These are acid's main characteristics. While Alkalis are a subset of Bases. They release Hydroxide Ion (OH-) when they are mixed/dissolved in water. Alkalis taste sour, and they are very slippery. Acids have a pH less than 7, and Alkalis have a pH higher than 7. So, the pH scale helps us determine how acidic or alkaline a solution is! These substances are important in many industries such as manufacturing, drugs. etc.
Difference Between Acid vs Alkali
The key difference between these two types of substances lies in the ions they form, their pH scale range, and taste. It's interesting to note that acid and alkali react; they can neutralize each other to produce water and salt!
| Property | Acid | Alkali |
| Ion Released in Water | Hydrogen ion (H⁺/H₃O⁺) | Hydroxide ion (OH⁻) |
| pH Value (Room Temp: 25°C) | Less than 7 | Greater than 7 |
| Touch & Taste | Not Slippery, Sour | Slippery & Bitter |
| Reaction with Metal | May Produce Hydrogen Gas | Usually Doesn’t React Directly |
| Litmus Paper/Indicator Effect | Turns Blue Litmus Into Red | Turns Red Litmus Into Blue |
| Example | HCl, H₂SO₄, CH₃COOH | NaOH, KOH, NH₃(aq) |
Explaining the pH Scale
The pH scale measures the concentration of hydrogen ions. It is logarithmic as such; if the pH value changes by 1 unit, then the acidity or hydrogen ion concentration changes tenfold! At room temperature (25°C), neutral water has a pH value near 7. While acidic solutions have a pH below 7, alkaline solutions have a pH above 7. Note:
- Strong acids have a pH value near 0.
- Strong alkalis have a pH value close to 14.
Physical & Chemical Properties of Acid-Alkali
Acid is corrosive! Strong acids (Example: Hydrochloric Acid) can completely ionize in water, while weak acids dissolve only partially. Alkalis react with skin oils, making them slippery. However, in concentrated form (Example: Caustic Soda), alkalis can be corrosive as well.
Acid-Alkali Neutralization Reaction
| General Reaction | Acid + Alkali → Salt + Water |
| Example | HCl + NaOH → NaCl + H₂O |
Strength and Concentration
Concentration means how many moles of solute (Acid or Alkali) are present in per litre of solution. Strength means how much of the solute dissolves. Strong acids or alkali can ionize/dissolve almost completely at a given temperature. A weak acid or alkali dissolves only partially and remains reactive.
Example
- Acetic acid is concentrated in vinegar. But it’s still a weak acid.
- Diluted Sodium Hydroxide is still a strong base.
Application of Acid & Alkali
Some of the common uses of applications of acid and alkali are:
| Acid Application | Alkali Application |
| Cleaning Agent | Detergent and Soap |
| Food Preservation | Water Softening |
| Industrial manufacturing | Chemical Industry |
How to Safely Handle Acid & Alkali
Both acids and alkalis are harmful to the skin, eyes, lungs, etc. Their corrosion property can weaken metal containers. So, it requires discipline and training to work with these. Important tips to handle these substances properly:
- Use Prospective Gear: Gloves, Googles, Chemical-Resistant Cloth, etc.
- Dilute the acid with water.
- Store Acids and Alkalis properly in separate containers.
- Don't mix chemicals without following proper instructions.
How Indicators Differentiate Between Acid and Alkali
Paper strips are great for a quick visual check. When mixed with acid or alkali, litmus paper switches colors. While universal indicators offer a graded color change. For alkali titrations, phenolphthalein is often used. However, for accurate readings, we need to use meters.
Litmus Paper Indicator
- Acid turns blue litmus paper red.
- Alkali turns red litmus paper blue.
Universal Indicator
Spans the whole scale.
Phenolphthalein
- Colorless when mixed with an acidic solution.
- Pink when mixed with a base
pH Meter
Calibration using a standard buffer.
How We Use Acids and Alkalis in Everyday Life
It may amaze a lot of people, but household ingredients like vinegar or lemons have acids. While baking soda has alkali in it. Batteries use a strong acid (Sulfuric Acid) electrolyte. Even the ingredients we use to clean our house or clothes contain these chemicals. If you look at the labels of household products, you may find these chemicals listed!
- Food: Citric Acid, Carbonic Acid(In Drinks).
- Cleaning Agent: Sodium Carbonate, Ammonia Solutions, Caustic Soda.
- Water Treatment: Lime and Soda Ash.
Importance of Acids and Alkalis In Industries
These chemicals are used in many industries in the UAE. Like Water Treatment Plants use Hydrochloric Acid and Sodium Hydroxide. There are oil fields and manufacturing industries that use advanced, eco-friendly tech to produce and supply these chemicals safely. For example, Kobray is a reputable online supplier where you can find acids and alkalis.
When choosing a supplier, verify their batch certificates, match grades, ask about packaging and delivery process, etc. Compare the sellers in the nearest locations and request samples. Audit the supplier products regularly.
Read More: Top 10 Wholesale Suppliers in UAE for Best Deals
Frequently Asked Questions About Acids and Alkalis
What is the difference between an acid and an alkaline substance?
Acids release hydrogen ions (H⁺) in water, while alkaline substances release hydroxide ions (OH⁻).
How do acids and alkalis differ in pH and ion production?
Acids have a pH below 7 and increase the hydrogen ion (H⁺) concentration. Alkalis have a pH above 7 and increase the hydroxide ion (OH⁻) instead.
How do household alkalis compare to commercial-grade alkalis?
Household alkalis like baking soda or mild ammonia are weak and safe for everyday use. Commercial alkalis, such as sodium hydroxide, are very strong and require strict safety measures.
What are five common alkalis?
Five common alkalis are NaOH (Sodium Hydroxide/Caustic Soda), KOH (Potassium Hydroxide), Ca(OH)₂ (Calcium Hydroxide/Quick Lime), NH₄OH (Ammonium Hydroxide), and Na₂CO₃ (Sodium Carbonate/Washing Soda).
How can I neutralize an alkali spill safely at home?
Use mild acid, like vinegar or lemon juice, to neutralize the alkali.
Is coffee acidic or alkaline?
Coffee is acidic. It contains several natural acids like (Citric acid, Acetic acid, Phosphoric acid, etc.) and has a pH between 4.8 to 5.1. The natural acids contribute to its taste and aroma.
Is vinegar an acid?
Yes. Vinegar contains acetic acid (Usually About 5%). It has a pH of 2–3. That’s why it tastes sharp and sour.
What pH is Coca-Cola?
Coca-Cola is acidic, with a pH around 2.5. Its acidity comes from carbonation and phosphoric acid.
Is soap an acid or a base?
Soap is a base. Most soaps are mildly alkaline, with a pH between 9-10. This is why they are slippery.
Is milk an acid or a base?
Milk is slightly acidic, with a pH of 6.5 to 6.7. It’s close to neutral, which is why it feels gentle on the stomach.
