Identification Of Metal Ions And Nonmetal Ions

Question 1

How do we test for carbonates ?

Answer 1

Overall: if a carbonate reacts with an acid it forms a salt+ CO2 + H2O
1. Add dilute HCL to our test sample
2. Take any gas produced and run it through limewater- turns cloudy

Question 2

How do we test for sulfates ?

Answer 2

1. Add dilute HCL to test tube to remove any impurities
2. Add barium chloride solution
   If sulfate ions are present a white precipitate will form

Question 3

How do we test for halides ?

Answer 3

1. Add 4 drops of dilute nitric acid to remove any impurities
2. Add silver nitrate (will react with the halides to form a colored precipitate)
   Chloride- white precipitate
   Bromide- cream precipitate
   Iodide- yellow precipitate

Question 4

Give the method for how we test for metal ions ?

Answer 4

1. Get the solution of metal and then add Sodium Hydroxide NaOH and see what colour the precipitate is

Question 5

How do we test for magnesium and what color will it appear as ?

Answer 5

We add NaOH
There should be a white precipitate

Question 6

How do we test for calcium and what colour will the precipitate be ?

Answer 6

Add NaOH
The precipitate should be white

Question 7

How do we test for aluminum and what colour will the precipitate be ? How do we make sure it is aluminum ?

Answer 7

Add NaOH but it will dissolve in excess meaning we know it’s aluminum
White precipitate

Question 8

How do we test for Iron+2 and what colour will the precipitate be ?

Answer 8

Add NaOH
Should be a dark green precipitate

Question 9

How do we test for iron +3 and what color will the precipitate be ?

Answer 9

Add NaOH
Color of precipitate should be orange/ brown

Question 10

How do we test for copper and what color will the precipitate be ?

Answer 10

Add NaOH
Color should be blue

Question 11

What’s the difficulty when testing for magnesium, calcium and aluminum ?

Answer 11

They all have the same color precipitate (white)
To fix this we see if it dissolves in excess NaOH, if it does it’s aluminum
And then to test if it’s calcium or magnesium we do a flame test to see the colour flame