Chapter 12 SULFUR

1. Sir. Muhammad Abdul Mageid
CIE - IGCSE Chemistry
Chapter 12 SULFUR
12.2 – Sulfur dioxide

2. Contents
12.2 –Sulfur dioxide
12.1- Sulfur – The element
12.3 – Sulfuric acid
Sir. Muhammad Abdul Mageid

3. Saturday, August 15, 2020
12.2 – Sulfur dioxide
Sulfur dioxide
 Sulfur dioxide can be made by the direct combination of sulphur
with oxygen
 This is the method used in the first stage of the manufacture of
sulfuric acid: 𝑺(𝒔) + 𝑶 𝟐(𝒈) → 𝑺𝑶 𝟐(𝒈)
 The gas dissolves in water to produce an acidic solution of
sulfurous acid : sulfur dioxide + water → sulfurous acid
𝑺𝑶 𝟐(𝒈) + 𝑯 𝟐 𝑶(𝒍) → 𝑯 𝟐 𝑺𝑶 𝟑(𝒂𝒒)
Sir. Muhammad Abdul Mageid

4. Saturday, August 15, 2020
12.2 – Sulfur dioxide
Test for sulfur dioxide :
 Sulfur dioxide will turn acidified potassium manganate(vii)
solution from purple to colourless
Sir. Muhammad Abdul Mageid

5. Saturday, August 15, 2020
12.2 – Sulfur dioxide
Acid rain
Sir. Muhammad Abdul Mageid

6. Acid rain
Saturday, August 15, 2020
 Rainwater is naturally acidic since it dissolves carbon dioxide gas
from the atmosphere as it falls. Natural rainwater has a pH of
about 5.7. In recent years, especially in central Europe, the pH of
rainwater has fallen to between pH 3 and pH 4.8.
This increase in acidity has led to extensive damage to forests,
lakes and marine life.
 In addition it has led to the increased corrosion of exposed
metals and to damage to buildings and statues made from
limestone or marble
Sir. Muhammad Abdul Mageid

7. Acid rain
Saturday, August 15, 2020
Mechanism of corrosion ( damage ) of buildings and statues made
from limestone
 Word Equation :
Limestone +sulfuric acid → calcium sulfate + water + carbon dioxide
 Symbolic Equation :
𝐶𝑎𝐶𝑂3(𝑠) + 𝐻2 𝑆𝑂4 → 𝐶𝑎𝑆𝑂4(𝑠) + 𝐻2 𝑂(𝑙) + 𝐶𝑂2(𝑔)
Sir. Muhammad Abdul Mageid