Group 7: Halogens
Read our general notes on Risk Assessment
What are the products of the reactions between potassium chloride, bromide and iodide with phosphoric acid?
Igloo replies ...
With potassium chloride the gas evolved is hydrogen chloride and the solid product remaining is mostly potassium dihydrogenphosphate:
KCl + H3PO4 -> KH2PO4 + HCl
There may also be small amounts of dipotassium hydrogenphosphate (K2HPO4) and even tripotassium phosphate (K3PO4) formed as well.
Using the other two halides, the same solid products are produced, together with gaseous hydrogen bromide or hydrogen iodide.
Phosphoric acid is a non-oxidising acid so, unlike concentrated sulfuric acid, it gives the hydrogen halide with all three halides.
Risk assessment
Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website.
For further guidance see our tutorial on Risk Assessment.
Rate this page or react
Share your views on this page, 5 ratings so far
, rated at 
updated: 11 February 2004
