Question

RESULTS:

  Exercise 1: Qualitative Anion Tests

Data Table 1. Anion Confirmation Tests.

Chemical	Anion	Addition of AgNO3	Addition of HCl
NaBr	Bromide	It became white and cloudy	Still was white and cloudy
Na2CO3	Carbonate	Clear inside white and cloudy around the outside	Still white and cloudy but bubbles start to form.
NaCl	Chloride	Turn white cloudy on bottom clear on top	Still white cloudy on bottom clear on top
NaI	Iodide	In the middle very dark and cloudy fades out lighter white around the middle	Became a little seperate
Na2SO4	Sulfate	clear	Became white and cloudy
Na2S	Sulfide	Turn a brown color in the middle but separated from the clear	The brown becomes more separate from the clear
Unknown #103	carbonate	White and cloudy	White and cloudy bubbles form
Unknown #104	sulfide	Turn brown color in the middle	Some of the brown disappeared and became seperate

Use your results and observations in Data Table 1 to create a flow chart for identification of unknown anions, using the AgNO₃ and HCl confirmation tests. Insert the flow chart below.

Data Table 2. Cation Flame Tests.

Chemical	Cation	Flame Observations
KI	Potassium	light pink
CaCl2	Calcium	Red
LiOH	Lithium	Dark pink
NaCl	Sodium	Orange
Cu(NO3)2	Copper	Light blue
Unknown #105	copper	Light blue
Unknown #106	potassium	Light pink
Unknown #107	calcium	red

Data Table 3. Complete Chemical Identification.

Chemical	Cation	Anion Test Observations	Anion	Complete Chemical Name and Formula
Unknown #105	copper	No change	No3^2-	Copper nitrate
Unknown #106	potassium	Dark in the middle and fades lighter	l-	Potassium iodide
Unknown #107	calcium	Turn white and clouy	Cl-	Calcium chloride

Use your results and observations in Data Tables 1, 2, and 3, to create a flow chart for the identification of an unknown (both an unknown anion and cation), using the AgNO₃ and HCl confirmation tests and the cation flame tests.

Answer 1

As given in the tables and data

Unkown 103

(i) Unkown anion : It is becomes white and cloudy on addition of AgNO3 and bubbles are formed on addition of HCl so it must be carbonate.

Unkown 104

(i) unkown anion: Turn brown color in the middle on additon of AgNO3 : it must be bromide ion

Cation flame tes

(i) Unkown 105: Light blue colour so must be copper ion

Unknown 106 :Light pink so must be potassium cation

Unkown 107 : Red colour so must be Calcium ion

(ii) for anion

Unkown 105 : No change on addition of AgNO3 : so the anion must be nitrate ion

So the salt is Cu(NO3)2

Unkown 106: Dark in the middle and fades lighter: so must be iodide ion

The salt will be

KI

Unknown 107 : Turn white and cloudy: chloride ion

so the salt is CaCl2

The flow chart will be

Step 1: Addition of AgNO3 to three unkown

a) White ppt forms with 107 so : Chloride ion is present

b) Dark in the middle and fades lighter: Iodide ion is present

c) No change:Nitrate ion is present

Flame test

(i) Red colour For 107 : Calcium ion is present

(ii) light pink for 106 : K+ is present

(iii) Light blue for 105: Copper ion is present