M8 cation test flow charts

Question 1

what are the cations that are being tested (7)

Answer 1

• Ba²⁺
• Pb²⁺
• Ca²⁺
• Cu²⁺
• Fe²⁺
• Fe³⁺
• Mg²⁺
• Ag⁺

Question 2

How many tests are there in the flowchart

Answer 2

3

Question 3

• What is the first test/s (1)
• What are the results of each(2)
• What are the validations for each of the results (2)

Answer 3

Add Hydrochloric acid (HCL)

Results: (Pb²⁺, Ag⁺)

1. Pb²⁺₍ₐᵩ₎ + 2Cl⁻₍ₐᵩ₎ ➝ PbCl₂₍ₛ₎ (white ptte)
2. Ag⁺₍ₐᵩ₎ + Cl⁻₍ₐᵩ₎ ➝ AgCl₂₍ₛ₎ (white ptte)

Validations:

1. Pb²⁺ + 2I⁻ ➝ PbI₂₍ₛ₎ (yellow ptte)
2. Ag⁺ + 2NH₃ ➝ Ag(NH₃)₂ (colourless)

Question 4

• what is the second test
• what are the results of each(4)
• What are the validations for each of the results(3)

Answer 4

Add sodium hydroxide (NaOH)

Results: (Cu²⁺, Fe²⁺,Fe³⁺,Mg²⁺)

1. Cu²⁺ + 2OH⁻ ➝ Cu(OH)₂ (blue ptte)
2. Fe²⁺ + 2OH⁻ ➝ Fe(OH)₂ (yellow-green ptte)
3. Fe³⁺ + 3OH⁻➝Fe(OH)₃ (Brown ptte)
4. Mg²⁺ + 2OH⁻ ➝ Mg(OH)₂ (white ptte)

Validations:

1. Cu²⁺ + 4NH₃ ➝ Cu(NH₃)²⁺ (Dark Blue complex)
2. Fe²⁺ + 2Fe(CN)₆➝ Fe₃(Fe(CN))₂ (Dark blue complex)
3. Fe³⁺ + SCN⁻ ➝ FeSCN²⁺ (Blood Red ptte)
4. ???

Question 5

• what is the third test
• what is the result of each
• what are the validations for each of the results

Answer 5

Add Sodium fluoride (NaF)

Results: (Ca²⁺,Ba²⁺)

1. Ca²⁺ + 2F⁻ ➝ CaF₂ (white precipitate)
2. Ba²⁺ no precipitate

Validations:

1. Ca²⁺: Flame test = blood red (orange red)
2. Ba²⁺: Flame test = yellow-green