Question 34
[Maximum number: 1]
Which statement identifies a sample of water as pure?
A
It melts at room temperature.
B
It turns anhydrous copper(II) sulfate blue.
C
It turns hydrated cobalt(II) chloride from blue to pink.
D
It boils at .
CAIE IGCSE Chemistry 10.1.2 To test for the purity of water using
Practise purity testing by using melting and boiling points to distinguish pure water from water containing impurities.
How this is tested
- use a sharp boiling point of 100 °C or freezing point of 0 °C as evidence for pure water
- explain that dissolved impurities raise the boiling point above 100 °C