Sample Test 10

Analysis of Solid M

Test Procedure

You are provided with solid M. Carry out the tests below. Write your observations and inferences in the spaces provided below.

  • (a)Place all solid M in a boiling tube, add about 5cm3 of distilled water and shake well. Filter the mixture. Divide the filtrate into two portions. Retain the residue for further tests.
    • (i) To the 1st portion of the filtrate, add a few drops of lead (II) nitrate solution. Warm the mixture.
    • (ii)To the second portion, add 1cm3 of sodium hydroxide. Heat the mixture gently and test the gases produced using blue and red litmus papers
  • (b)Scrap the residue gently from the filter paper with a spatula and place it in the test tube. Add 2cm3 of nitric (v) acid. Divide the resulting solution into two portions.
    • (i)To the 1st portion, add sodium hydroxide until in excess
    • (ii)To the 2nd portion, add aqueous ammonia dropwise until in excess

Tips: To start, ...click on boiling tube in the display rack to select it before placing the sample.
Follow the procedure sequentially and the sytem monitor instructions.

Tips on the system color code

Colourless Solution

White Precipitate

Workbench

VIRTUAL WORKBENCH MONITOR Selected: None
System Initialised. Select boiling tube to start step 1.
Main
T₁
 
T₂
T₃
T₄
T₄


STUDENT LABORATORY WORKBOOK

Procedure Observations Inferences
(a) Solid M in boiling tube + 5cm3 distilled water, shaked well, filtered & divided the filtrate into 2 portions: 1st portion of fitrate + a few drops of PbNO3 solution + warmed the miixture.
(ii) 2nd portion + 1 cm3 of NaOH + Heated the mixture gently + tested the gas produced with red & blue litmus papers
(b) Scraped the residue gently from the filter paper into a test tube + added dilute HNO3. Divided into 2 portions
(i)1st portion + NaOH drowise until in excess
(ii) To the 2nd portion + ammonia dropwise till in excess

OFFICIAL MARKING SCHEME & EXPECTED RESPONSES

Procedure Observations Inferences
(a) Solid M in boiling tube + 5cm3 distilled water, shaked well, filtered & divided the filtrate into 2 portions: 1st portion of fitrate + a few drops of PbNO3 solution + warmed the miixture. white precipitate that does not dissolve on warming

(1 mark) 		SO4 2- present.

(1mark)
(ii) 2nd portion + 1 cm3 of NaOH + Heated the mixture gently + tested the gas produced with red & blue litmus papers Gas produced turns red litmus paper red. No effect on blue litmus paper

(1 Mark) 		NH3+ present

(1 mark)
(b) Scraped the residue gently from the filter paper into a test tube + added dilute HNO3. Divided into 2 portions
(i)1st portion + NaOH drowise until in excess		 White precipitate dissolves in excess to form a colourless solution. (must indicate colour of the solution)

(1 mark) 		Zn2+, Al3+,Pb2+ present

(1 mark)
(ii) To the 2nd portion + ammonia dropwise till in excess White precipitate that does not dissolve in excess

(1 mark) 		Al3+, Pb2+ present

(1 mark)

Identity of solid E: Hydrated Ammonium Aluminium sulphate + Magnesium Carbonate