acids and bases

 acids and bases

Acids: 
substances that produce hydrogen ions in aqueous solution. (H+ ions)
e.g: HCl (hyrdochloric acid) has a positive hydrogen ion (H+) and a negative Cl ion (Cl-)

Properties: (physical)
- acids are corrosive
- acids have a sour taste
- soluble in water
- when dissolved in water, acids form a solution which conducts electricity.

Types Of Acids: 

organic acids: are natural and are weak, they only partially ionize in water, which means when they are ionized they can combine once again. (reversible) 
e.g: carbonic acid (H2CO3), lactic acid.

mineral acids: are synthesized in labs and are strong, they completely ionize in water, which means that when they are ionized they can not combine together again. (irreversible) 
e.g: sulfuric acid (H2SO4), nitric acid (HNO3)

Basicity Of Acids: 
the amount of hydrogen ions an acid produces in an aqueous (liquid) solution.
e.g: 
H₂CO₃ = H₂ + CO₃ > this means that carbonic acid has a basicity of 2. 

Properties: (chemical)
reaction of acids with metals: 
acid + metal = salt + H₂
e.g: HCl + Mg = MgCl + H₂

reaction of acid with metal carbonate: 
acid + metal carbonate = salt + water + carbondioxide
e.g: MgCo₃ + H₂SO₄ = MgSo₄ + H₂O + Co₂

reaction of acids with base: 
acid + base = salt + water
e.g: HCl + Na₂O = NaCl + H₂O


Bases:
metal oxides and metal hydroxides are called bases.
Alkali: substances which give OH- ions in an aqueous solution.
alkali's are a type of base, they are soluble in water 

Properties: (physical)
- slippery
- bitter in taste
- mostly insoluble in water (alkali's are soluble)
- when dissolved in water, it can conduct electricity. 

Alkali: 
- all of the group 1 and 2 elements are alkaline (except for the first 2 in group 2 [beryllium and magnesium]) 
- all alkali's are bases
- are highly reactive 
- form hydroxides in water. 

electrolytes: particles that can conduct electricity in an aqueous (liquid) state.
this is a better terminology to use, instead of  "can conduct electricity when dissolved in water"

Properties: (chemical)
reaction of base with acids: 
acid + base = salt + water
e.g: HCl + Na₂O = NaCl + H₂O

reaction of base with ammonium salt: 
base + ammonium salt = salt + water + ammonia gas


Indicators And The PH Scale: 
the pH scale measures how acidic a substance is.

pH: power of  H+

lower than 3: strong acid
more than 3: weak acid
less than 7: acid
more than 7: base
less than 10: strong base
more than 10: weak base

Indicators: are the substances which change color in acidic or basic medium. 

Litmus Paper: 
normal color: red and blue

in acids: the red stays red and the blue turns red
in bases: the blue stays blue and the red turns blue

Phenolphthalein: 
normal color: colorless
in acids: colorless
in bases: pink

Methyl Orange:
normal color: orange
in acids: red
in bases: pink

Thymolphthalein: 
normal color: colorless
in acids: colorless
in bases: blue

Universal Indicator
normal color: -
in acids: orange/red
in bases: blue/violet