State the main difference between acid and base
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Definition. A substance, mostly liquid that donates a proton or accepts an electron pair in reactions. An acid increases the concentration of H+ ions. A base is a substance that releases hydroxide (OH-) ions in aqueous solution, donates electrons and accepts protons.
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Explanation:
Acids and Bases play an important role in chemistry. We see them everywhere in our day to day lives, from our cleaning agents; soaps and detergents, to baking soda. Acids and bases (alkaline earth metal chemical element) are 2 categories of corrosive substances. Any compound with a pH value between zero to seven is considered acidic, whereas a pH value between seven to fourteen is a base. An acid is called a proton donor, while a base is called a proton acceptor (Kolb, 1978).
Difference in Definition
Acid
An acid is a molecule or substance that has a pH value less than 7.0 when it is present in an aqueous solution. An aqueous solution is any solution where water is a solvent. Acids are termed as compounds that donate H+ (hydrogen ion) to another compound known as base.
Base
A base (alkaline) is a molecule or substance that has a pH value higher than 7.0 when present in an aqueous solution. Bases are the exact chemical opposite of acids. In chemistry. They are substances that, in aqueous solution, release hydroxide (OH−) ions.
Arrhenius Concept (Ouertatani et al, 2007)
Acids
As per Arrhenius Concept, an acid elevates the concentration of Hydrogen ions when dissolved in water.
Bases
As per Arrhenius Concept, a base is a compound that increases the concentration of hydroxide ions (OH–) when dissolved in water.
Bronsted-Lowry Concept (Kauffman, 1988)
Acids
In the Bronsted-Lowry Concept, acids are substances which donate protons
Bases
Bases, on the other hand, are substances which accept protons
Lewis Concept (Brewer, 1984)
Acids
Ions that accept the pair of electrons (electron pair acceptor – an electrophile), and possess vacant orbitals are termed ‘Lewis acid’.
Bases
Ions that donate a pair of electrons (electron pair donor – a nucleophile), and possess a lone pair of electrons are termed ‘Lewis base’.
Difference in Classification
Acids
Acids are classified as:
Strong acids, such as nitric acid (HNO3), sulfuric acid (H2SO4), and hydrochloric acid (HCl) respectively.
Strong Lewis acids, such as AlCl3 (anhydrous aluminium chloride) and BF3 (boron trifluoride).
Concentrated weak acids, such as acetic acid (CH3COOH) and formic acid (CH2O2).
Lewis acids with specific reactivity, for example; solutions of ZnCl2 (zinc chloride).
Superacids, which are extremely strong acids.
Bases
Bases are classified as:
Alkalis or Caustics, such as NaOH (sodium hydroxide) and KOH (potassium hydroxide).
Concentrated weak bases, such as NH3 (ammonia) in a concentrated solution.
Alkali metals in metallic form, (i.e. elemental sodium), and hydrides of alkaline and alkali earth metals, i.e. NaH (sodium hydride), which function as a strong hydrate and bases to produce caustics.
Superbases, which are extremely strong bases, such as metal amides, alkoxides, (i.e. NaNH2 – sodium amide) and C4H9Li (butyllithium), which is an organometallic base.
Difference in Chemical Formula
Acids
The chemical formula for most acids starts with H. For example, Nitric acid (HNO3), Carbonic acid in soft drink (H2CO3), Boric acid (H3BO3), Hydrochloric acid (HCl), Oxalic Acid (H2C2O4), Citric Acid or 2-Hydroxy-1,2,3-propanetricarboxylic acid (H3C6H5O7), and Sulfuric acid (H2SO4). However, there are exceptions like Acetic Acid (CH3COOH).
Bases
The chemical formula for most bases (compounds) has OH at the end. For example, Calcium hydroxide or slaked lime, Ca (OH)2 (paper, flocculant), Magnesium hydroxide (Mg (OH)2) or milk of magnesia, Sodium hydroxide (NaOH) or caustic soda (cleaning agent, pH regulator), Ammonium hydroxide (NH4OH) or ammonia water and KOH (Potassium hydroxide).
Difference in pH
Acids
Acids have a pH less than 7.0.
Bases
Bases have a pH higher than 7.0, and could even go up to 14 if the bases are very strong.
Strength of Acids and Bases
Acids
The strength of acids depends on the concentration of hydronium ions (Umansky, 1991).
Bases
The strength of bases depends on the concentration of hydroxide ions.
Differences in Physical Characteristics
Both acids and bases are different in their physical properties.
Acids
When dissolved in water, acids
Are Sticky
Have a burning sensation
Change blue litmus to red color
Are sour in taste
React with bases for neutralization of their properties
Conduct electricity
React with active metals to liberate H (Hydrogen)
Remain colorless when Phenolphthalein is added to the solution.
Bases
When dissolved in water, bases
Are bitter in taste
Are (except ammonia)
Change red litmus to blue color
Are slippery to the touch
React with acids to neutralize their respective properties
Turn pink when Phenolphthalein is added to the solution.
Difference in Ionization
Acids
Acids are species or compounds that break apart in H2O to form a hydrogen ion (H+). So, it can be said that acids form Hydronium ions on ionization (Schultz, 1997).
Bases
Bases result in Hydroxyl ions on ionization (Nyasulu et al, 2013).
Difference in Dissociation
Acids
Acids release H+ (Hydrogen ions) when mixed with water (H20).
Bases
Bases release OH– (Hydroxide ions) when mixed with water (H20).
Differences in Uses
Acids
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