Acids, Bases & Salts

Page
5

Slide 20

TYPES OF OXIDES

Topic 10: ACIDS, BASES & SALTS

20

:

BASIC OXIDES

On the left and middle of the Periodic Table are the basic metal oxides eg Na2O, MgO, CuO etc

They react with acids to form salts. e.g

2HCl + MgO ------------ MgCl2 + H2O

CuO + H2SO4 ------------- CuSO4 + H2O

These metal oxides tend to be ionic in bonding character with high melting points.

As you move left to right the oxides become less basic and more acidic.

جمعرات، 28 ربیع الثانی، 1438

Slide 21

Topic 10: ACIDS, BASES & SALTS

21

TYPES OF OXIDES

ACIDIC OXIDES: On the right of the Periodic Table the acidic oxides of the non-metals are present e.g. CO2, P2O5, SO2, SO3 etc.

These tend to be covalent in bonding character with low melting/boiling points.

Those of sulphur and phosphorus are very soluble in water to give acidic solutions which can be neutralised by alkalis to form salts.

SO2 + H2O ----------- H2SO3

SO3 + H2O ----------- H2SO4

جمعرات، 28 ربیع الثانی، 1438

Slide 22

Topic 10: ACIDS, BASES & SALTS

22

TYPES OF OXIDES

AMPHOTERIC OXIDES:

They are metallic oxides.

They react with both acids and alkalis.

They are usually relatively insoluble and have little effect on indicators.

An example is aluminium oxide dissolves in acids to form 'normal' aluminium salts like the chloride, sulphate and nitrate. However, it also dissolves in strong alkali's like sodium hydroxide solution to form 'aluminate' salts.

جمعرات، 28 ربیع الثانی، 1438

Slide 23

Topic 10: ACIDS, BASES & SALTS

23

TYPES OF OXIDES

NEUTRAL OXIDES:

They are non- metallic oxides.

They tend to be of low solubility in water and have no effect on litmus.

do not react with acids or alkalis. eg CO carbon monoxide and NO nitrogen monoxide, H2O.

There is no way of simply predicting this kind of behavior from periodic table patterns!

جمعرات، 28 ربیع الثانی، 1438

Slide 24

Topic 10: ACIDS, BASES & SALTS

24

PERIODIC TRENDS IN OXIDES