ANALYSIS Flashcards
flame test for Ca++ ions
brick red
flame test- brick red
Ca++
flame test for Na+ ions
intense yellow
Flame test - intense yellow
Na+
flame test - green flame with a blue centre
Cu++
flame test for Cu++ ions
green with a blue centre
flame test- lilac
K+
flame test for K+ ions
lilac flame
flame test - bright red
Li+
flame test for Li+ ions
Bright red
flame test results with no colouration
Mg++ or NH4+
flame test for Mg++
no colouration
flame test for NH4+ ions
no colouration
initial appearance of a Cu++ ion
blue
initial appearance of a Cu++ or Fe++ ion
green
initial appearance of a Fe+++ ion
yellow
initial appearance of a Fe+++ ion
brown
initial appearance of an uncombined metal
shiny grey or black
initial appearance of a non transition metal ion
white powder or colourless solution
Test for NH4+, ammonium ions
NH4+ (s) OH-(aq) -> NH3(g) + H2O(g)
1) it has a pungent smell
2) turns damp litmus blue ( its the only common alkaline gas. make sure the paper is in the gas and not the sodium hydroxide solution as this can also turn the litmus blue) - must be damp so the ammonia has forms hydroxide ions which change the colour of the litmus paper.
3) with a stopper from a bottle of concentrated hydrochloric acid it gives a white smoke -ammonium chloride
NH3(g) + HCl(g) -> NH3Cl(s)
how do you perform a flame test
1) Use a platinum flame test rod and dip it into hydrochloric acid to clean it of any impurities and place in a non-luminous flame.
2) Then dip the clean rod into the substance and then back into the acid (which acts as a type of glue) then back into the unknown substance
3) The place into the bunsen burner and observe the colour of the flame.
