Identification Of Ions Flashcards
What are flames tests used for
Metal ions
What are we testing for when using aqueous sodium hydroxide or aqueous ammonia
Cations.
branch of chemistry that uses tests to identify gases and ions
Qualitative analysis
Ammonia
Test
Turns damp red litmus paper blue
Carbon dioxide (CO2)
Test
Turns limewater milky
Chlorine (Cl2)
Test
Bleaches snap litmus paper white
Hydrogen (H2)
Test
Makes a lighted splint go pop when held over
Oxygen (O2)
Test
Reignites a glowing splint
Sulfur dioxide (SO2)
Test
Turns acidified aqueous potassium manganate (VII) from purple to colourless
Identify carbonate CO3 2-
React with dilute acid the test for carbon dioxide gas (turns limewater milky)
Effervescence, carbon dioxide produced
Identify Chloride in a solution
Cl-
Acidify with dilute nitric acid and add aqueous silver nitrate
White ppt.
Identify Bromide in a solution
Br-
Acidify with dilute nitric acid then add aqueous silver nitrate
Cream ppt.
Identify iodide in a solution
I-
Acidify with dilute nitric acid, add aqueous silver nitrate
Yellow ppt.
Identify nitrate in a solution
NO3 -
Add aqueous sodium hydroxide then aluminium foil and warm carefully
Ammonia produced (turns damp red litmus paper blue)
Identify sulphate in a solution
SO4 2-
Acidify with dilute nitric acid then add aqueous barium nitrate
White ppt.
Identify sulfite in a solution
Add a small volume of acidified aqueous potassium manganate (VII)
The acidified aqueous potassium manganate (VII) turns from purple to colourless
Identify aluminium
In aqueous sodium hydroxide: white ppt. Soluble in excess giving a colorless solution
In aqueous ammonia: white ppt. Insoluble in excess
Identify ammonium
NH4+
In aqueous sodium hydroxide: ammonia produced on warming
In aqueous ammonia: nothing
Identify calcium
Ca 2+
In aqueous sodium hydroxide: white ppt. Insoluble in excess
In aqueous ammonia: no ppt. Or very slight white ppt.
Identify chromium (III)
Cr 3+
In aqueous sodium hydroxide: green ppt. soluble in excess
In aqueous ammonia: grey-green ppt. Insoluble in excess
Identify copper
Cu 2+
In aqueous sodium hydroxide: light blue ppt. Insoluble in excess
In aqueous ammonia: light blue ppt. Soluble in excess giving a dark blue solution
Identify iron (II)
Fe 2+
In aqueous sodium hydroxide: green ppt. Insoluble in excess, turns brown near surface on standing
In aqueous ammonia: green ppt. Insoluble in excess, turns brown near surface on standing
Identify iron (III)
Fe 3+
In aqueous sodium hydroxide: red-brown ppt. Insoluble in excess
In aqueous ammonia: red-brown ppt. Insoluble in excess
Identify zinc
Zn 2+
In aqueous sodium hydroxide: white ppt. Soluble in excess giving a colourless solution
In aqueous ammonia: white ppt. Soluble in excess Giving a colourless solution
Tests for aqueous cations
Aqueous sodium hydroxide
Aqueous ammonia
Flame test lithium
Li+
Red flame
Flame test sodium
Na+
Yellow flame
Flame test potassium
K+
Lilac flame
Flame test calcium
Orange-red flame
Flame test barium
Light green flame
Flame test copper
Blue-green flame