- Taste and Touch: Bases have a bitter taste and feel soapy or slippery to the touch.
- Indicator Reaction: Bases turn red litmus blue, methyl orange yellow, and phenolphthalein pink.
- Soapy Reaction: Bases like caustic soda react with skin oils to form soap.
- Electrolytes: Strong bases are good conductors of electricity (strong electrolytes).
- Corrosive Nature: Bases can cause mild burns or skin irritation.
Definitions [6]
Define the term ‘basicity’ of an acid.
The basicity of an acid is defined as the number of hydronium ions (H3O+) that can be produced by the ionization of one molecule of that acid in aqueous solution.
Define Acid.
An acid is a compound which when dissolved in water produces hydronium ion(H3O+), the only positively charged
ion and a negative ion.
Definition: Acid
Acids are defined as compounds which contain one or more hydrogen atoms and when dissolved in water, produce hydronium ions (H3O+) the only positively charged ions.
Definition: Bases
A base is either a metallic oxide or a metallic hydroxide or ammonium hydroxide which reacts with hydronium ions of an acid to form a salt and water only.
Definition: Alkali
An alkali is a basic hydroxide which when dissolved in water produces hydroxyl (OH-) ions as the only negatively charged ions.
Define neutralization.
Neutralization: A chemical reaction in which a base or an alkali reacts, with an acid to produce salt and water only.
\[\ce{\underset{\text{sodium hydroxide}}{NaOH(aq)} +\underset{\text{hydro chloride acid}}{HCl(aq)}->\underset{\text{sodium cholride}}{NaCl(aq)}+\underset{\text{water}}{H2O}}\]
Key Points
Key Points: Physical Properties of Acids
- Taste & Safety: Acids taste sour; mineral acids are corrosive and should never be tasted.
- Physical State: Acids can be solids (e.g., boric acid) or liquids (e.g., HCl, H₂SO₄); some are volatile, others are not.
- Skin Effect: Strong acids cause burns; conc. H₂SO₄ chars skin, HNO₃ turns it yellow, HCl gives amber color.
- Indicators: Acids turn blue litmus red; also change colors of methyl orange and red cabbage extract.
- Conductivity: Acids conduct electricity in aqueous solutions, acting as electrolytes.
Key Points: Physical Properties of Bases
