Inorganic Tests and Methods

Question 1

(1) Appearance

Answer 1

Observe colour and state; say whether crystalline or power

Question 2

(2) Solubility in water

Answer 2

Add a few spatula measures of solid to a test tube of deionised water and shake to mix

Question 3

(3) Flame test

Testing for the presence of metal cations in the compound

Answer 3

Dip nichrome wire in concentrated HCl

Touch sample with the wire and hold in blue Bunsen flame

Question 4

(4) Concentrated sulfuric acid

Testing for halide ions

Answer 4

Place a spatula measure of solid sample in a test tube and add a few drops of concentrated sulfuric acid

Question 5

(5) Silver nitrate solution

Testing for halide ions

Answer 5

Dissolve a spatula measure of the sample in dilute nitric acid and add a few cm3️⃣ of silver nitrate solution
Add dilute ammonia solution
Add concentrated ammonia solution

Question 6

(6) Barium chloride solution

Testing for sulfate ions

Answer 6

Dissolve a spatula measure of the sample in dilute nitric (or hydrochloric) acid and add a few cm3️⃣ of barium chloride solution

Question 7

(7) Dilute nitric acid

Testing for carbonate/hydrogencarbonate ions

Answer 7

Place a few cm3️⃣ of dilute nitric acid in a test tube and add a spatula measure of sample

Question 8

(8) Magnesium nitrate/chloride solution

Distinguishing between carbonate/hydrogencarbonate ions

Answer 8

Dissolve a spatula measure of sample in deionised water and add a few cm3️⃣ of magnesium nitrate/chloride solution
If no ppt appears immediately, boil test tube contents

Question 9

(9) Potassium thiocyanate solution
Testing for iron(III) ions
Very sensitive

Answer 9

Dissolve a spatula of sample in deionised water and add a few cm3️⃣ of potassium thiocyanate solution

Question 10

(10) Potassium chromate(VI) solution

Testing for barium ions

Answer 10

Dissolve a spatula measure of sample in deionised water and add a few cm3️⃣ of potassium chromate(VI) solution

Question 11

(11) Sodium hydroxide solution

Testing for metal cations

Answer 11

Dissolve a spatula measure of sample in deionised water and add a few drops of sodium hydroxide solution
Then add about 5cm3️⃣ of sodium hydroxide solution (adding until in excess)

Question 12

(12) Sodium hydroxide solution

Testing for ammonium ions

Answer 12

Place a fee cm3️⃣ of sodium hydroxide solution in test tube and add a spatula measure of the sample
Test any gas evolved using damp UI paper or a glass rod dipped in concentrated HCl

Question 13

(13) Aqueous ammonia (dilute ammonia solution)

Testing for metal cations

Answer 13

Dissolve a spatula measure of sample in deionised water and add a few drops of aqueous ammonia
Then add about 5cm3️⃣ of aqueous ammonia (adding until in excess)