9.1 - Colorimetric Experiment to Estimate Free Chlorine in Swimming Pool Water or Bleach (Leaving Cert Chemistry): Flashcards

$HOCl$ (chloric(I) acid) and $ClO^-$ (chlorate(I) ions)

Iodine ($I_2$)

Directly proportional

Colorimeter

440 nm

Liberates iodine ($I_2$) with measurable colour

Provides acidic conditions for complete reaction

Sodium hypochlorite ($NaOCl$)

5 minutes

$\frac{71}{74.5}$

Quick, accurate, processes multiple samples efficiently

Ensures all chlorine reacts

2.5 $cm^3$

2%

5%