MCQ
Pick out the chemical change from the following:
- AMelting of ice
- ✓Burning of coal in air
- CFreezing of water
- DNone of the above
✓
Answer
Correct option: B.
Burning of coal in air
The burning of coal in the air is a chemical change:
$\ce{C + O_2 \rightarrow CO_2}$
If there is insufficient oxygen then carbon monoxide is formed:
$\ce{2C + O_2\rightarrow 2CO}$
Coal combustion releases nitrogen oxides, sulfur dioxide, particulate matter, mercury, and dozens of other substances known to be hazardous to human health.
Melting of ice and freezing of water are physical changes.
$\ce{C + O_2 \rightarrow CO_2}$
If there is insufficient oxygen then carbon monoxide is formed:
$\ce{2C + O_2\rightarrow 2CO}$
Coal combustion releases nitrogen oxides, sulfur dioxide, particulate matter, mercury, and dozens of other substances known to be hazardous to human health.
Melting of ice and freezing of water are physical changes.
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