Chemical Tests for Water
Chemical tests for water
Using cobalt(II) chloride:
- Cobalt(II) chloride turns blue to pink on the addition of water. This test is usually done using cobalt chloride paper
- The equation is:
anhydrous cobalt(II) chloride + water hydrated cobalt(II) chloride
CoCl2 (s) + 6H2O (l) CoCl2.6H2O (s)
blue pink
Test for water using cobalt chloride paper which turns pink in the presence of water
Using copper(II) sulfate:
- Anhydrous copper(II) sulfate turns white to blue on the addition of water
- The equation is:
anhydrous copper(II) sulfate + water hydrated copper(II) sulfate
CuSO4 (s) + 5H2O (l) CuSO4.5H2O (s)
white blue
Test for water using anhydrous copper(II) sulfate which turns blue in the presence of water
Exam Tip
Core students do not need to know the symbol equations.