Tests for Organic and Inorganic Ions
- Created by: lolza_98
- Created on: 08-05-16 20:14
Idoform Test
Testing for a CH3CH(OH)
A few cm3 of the liquid then add sodium hydroxide solution and idodine solution and warm
Yellow percipitate= CH3CH(OH)
Acidified Potassium Dichromate
Testing for a primary/secondary alcohol as opposed to tertiary alcohol
Mix a few cm3 of the liquid or solution with acidified potassium dichromate solution in a test tube and warm in water bath
Orange solution turns green= primary or secondary alcohol
Stays orange= not a primary or secondary
Phosphorous Pentachloride
Testing for an OH group
Add a few cm3 of the liquid and then add a few crystals of PCl5
Test any gas released with a glass rod dipped in concentrated ammonia solution
Gas released, misty fumes, solid disappears, heat released, white smoke= alcohol/OH group present; white smoke ammonia chloride
No gas released, no white smoke= no alcohol/OH group present
Silver Nitrate Solution
Testing for the presence of halogen atoms in a halogenalkane
Add one cm3 of halogenalkane to few cm3 of ethanol; add silver nitrate solution and warm in a water bath
White percipitate= chloroalkane
Cream perciptate= bromoalkane
Yellow percipitate= iodoalkane
Sodium Carbonate or Sodium Hydrogen Carbonate
Test for a COOH group
To a few cm3 of the liquid/solution add half a spatula measure of solid sodium carbonate or sodium hydrogen carbonate
Gas released, solid disappears, bubble through limewater goes cloudy= COOH group present
Magnesium
Testing for carboxlyic acid
Add a few cm3 of a liquid and then add a ***** of magnesium
Gas released, magnesium disappears, test gas with lit split- pop sound = carboxlyic acid
No gas = no carboxlyic acid
Appearance of Non-organic ions
Observe colour and state; say whether cystalline or solid
White crystaline solid= doesn`t contain transition metal/ not a metal compound, possibly compound of group 1,2 or ammonia compound
Blue= possibly contains copper ions, copper compound
Pale green= possibly contain 2+ iron ion/ iron compound
red-brown= possibly contains 3+ iron ion/ iron compound
Solubility in Water
Add a few spatula measures of solid to a test tube of deionised water
Dissolves to form a colourless solution= soluble in water, compound of group 1, 2, aluminium, zinc or ammonium
Dissolves to form a colourless solution= soluble in water, blue solution is copper, pale green is iron 2+, yellow/orange is iron 3+
Does not dissolve = insoluble in water
Sodium Hydroxide
Testing for Metal Cat ions
Dissolve a spatula measure of the sample in deionised water and add a few drops of NaOH solution. Then add about 5cm3 of NaOH
Pale green percipitate does not dissolve in excess NaOH = Iron 2+ present
Brown percipitate does not dissolve in excess NaOH = Iron 3+
White perciptate that does not dissolve in excess NaOH = Magnesium 2+
White percipitate dissolves in excess NaOH to form colourless solution= Aluminium 3+ or Zinc 2+
Magnesium Nitrate
Distinugishing between carbonate and hydrogencarbonate
Dissolve a spatula measure of the sample in deionised water and add a few cm3 of magnesium nitrate solution. If no percipitate immediately forms boil the contents.
White percipiate appears immediately = carbonate ions
Colourless solution, white percipitate, appears on boiling = hydrogencarbonate
No percipiate = no carbonate ions
Dilute Nitric Acid
Testing for carbonate ions and hydrogencarbonate
Place a few cm3 of dilute nitric acid in a test tube and add a spatula measure of the sample
Effervescence, solid disappears, gas evolved can be passed through limewater in other test tube = carbonate or hydrogencarbonate
Barium Chloride
Testing for Sulfate Ion
Dissolve a spatula measure of the sample in a dilute nitric acid and add a few cm3 of barium chloride soultion
white percipitate = sulfate ions
No percipitate = no sulfate ions
Potassium Chromate
Testing for Barium ions
Dissolve a spatula measure of the sample in deionised water and adda few cm3 of potassium chromate
Yellow percipitate that redissolves in dilute hydrocholric acid to form solution = Barium 2+
Potassium Thiocynate
Testing for Iron 3+
Dissolve a spatula measure of the sample in deionised water and add a few cm3 of potassium thiocynate
Blood red = iron 3+
Silver Nitrate Solution
Testing for halide ions
dissolve a spatula measure of the spatula in dilute nitric acid and add a few cm3 of silver nitrate solution. Add dilute ammonia solution. Add concentrated ammonia solution
White percipitate dissolves in dilute ammonia = chloride ion
Cream percipitate that does not dissolve in dilute ammonia but in concentrate ammonia = bromide ions
Yellow percipitate, does not dissolve in either = iodine ion
Concentrated Sulfuric Acid
Testing for halide ions
place a spatula measure of solid sample in a test tube and add a few drops of concentrated sulphuric acid
misty fumes when rod dipped in concentrated ammonia solution = chlordie ions, HCl fumes
misty fumes, red- brown vapour = bromide ions
misty fumes, purple vapour, rotten egg smell, yellow solid = idodide ions
Combustion
Place a few drops of the liquid on a watch glass and ignite with lit split
clean blue flame = low carbon content, possibly alcohol
sooty orange flame = high carbon content/ possibly alkane/ alkene
Appearance and smell of organic ions
colourless liquid with characteristic spirit/ alcohol smell = alcohol
fruit/ sweet smell = ester
colourless with sharp smell = carboxlyic acid/ ethanoic acid
Miscibility or solubility in water
Testing for polarity of the liquid
Add a few cm3 of the liquid to deionised water in a test tube
Mixes with water one layer formed = polar, possilbly alcohol/ carboxlyic acid
Two layer formed = Non- polar
Flame Test
Dip nichrome wire on concentrate HCl; touch sample with the wire, then hold out in a blue flame
Crimson = lithium
Yellow/ orange = sodium
Lilac = Potassium
Brick red = calcium
Green = Barium
Blue- green = copper
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