Acids, bases and neutralisation Flashcards Preview

CHEM - 2.1.4 - 2.1.5 Acids and Redox > Acids, bases and neutralisation > Flashcards

Flashcards in Acids, bases and neutralisation Deck (7)
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1

What are acids?

- Acids are proton donors as they release hydrogen ions when mixed with water.
e.g:
H2SO4 + H2O = 2H(+) + SO4(2-)
- Strong acids completely dissociates by releasing all Hydrogen atoms in aqueous solution:
HCl -> H(+) + Cl(-)
- Weak acids partially dissociates as only small proportion of hydrogen atoms are released as ions in aq. solutions:
CH3COOH <=> H(+) + CH3COOH(-)
<=> equilibrium sign indicates that forward reaction is incomplete.

2

Bases and alkalis

- Bases neutralise acid to form salts.
- Alkali is a base that dissolves in water and releases Hydroxide ions (OH-) in solution:
NaOH -> Na(+) + OH(-)

3

Neutralisation

- General formula of neutralisation reaction is:
Acid + Base -> Salt + Water
Ionic reaction:
H(+) + OH(-) -> H2O

4

Products of neutralisation

- Acid + METAL -> salt + hydrogen
- Acid + metal OXIDE* -> salt + water
- Acid + metal CARBONATE** -> salt + water = carbon dioxide

* reaction of metal hydroxide is the same as metal oxide ** reaction of metal hydrogen carbonate is the same as metal carbonate

5

Charges of some ions

NH4(+)

NO3(-), HCO3(-), Ethanoate: CH3COO(-)

SO4(2-), CO3(2-)

PO4(3-)

6

Partial and complete neutralisation reactions of carbonic acid w/ sodium hydroxide

NaOH + H2CO3 -> NaHCO3 + H2O
2NaOH + H2CO3 -> Na2CO3 + 2H2O

7

Why is sodium hydrogencarbonate called an acid salt?

One hydrogen atom has been replaced by a metal ion. The other hydrogen atom can still behave as an acid.