Test Procedure

You are provided with solid R, & solution T. Carry out the tests below and write down your observations and inferences in the spaces provided.

(a)Place all solid R in a boiling tube and add about 12cm3 of distilled water to dissolve.
Divide the resulting solution into 4 portions.
- (i)To the 1st portion, add 4 drops of Sulphuric (VI) acid
- (ii)To the 2nd portion, add NaOH solution dropwise until in excess
- (iii)To the 3rd portion, add 2 drops of aqueous potassium iodide solution
- (iv)To the 4th portion, add 4 drops of solution T

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

STUDENT LABORATORY WORKBOOK

Procedure	Observations	Inferences
(i) To about 2cm3 of solution E + 4 drops of 2M H2SO4
(ii) To about 2cm3 of solution E + 2M NaOH dropwise until in excess
(iii) To about 2cm3 of solution E + all solid F provided
(iv) To about 2cm3 of solution E in a test tube + 2 drops of potassium Iodide

OFFICIAL MARKING SCHEME & EXPECTED RESPONSES

Procedure	Observations	Inferences
(i) To about 2cm3 of solution E + 4 drops of 2M H2SO4	White precipitate (1 mark)	Pb2+, Ca2+, Ba2+ present (1mark)
(ii) To about 2cm3 of solution E + 2M NaOH dropwise until in excess	White precipitate which dissolves in excess (1 Mark)	Pb2+ present (1 mark)
(iii) To about 2cm3 of solution E + all solid F provided	White precipitate (1 mark)	F contains SO42-,SO32-,Cl-,CO32- (1 mark)
(iv) To about 2cm3 of solution E in a test tube + 2 drops of potassium Iodide	Yellow precipitate (1 mark)	Pb2+ confirmed present (1 mark)
		Identity of solid E: Lead (II) Nitrate - Pb(NO3)2 Solid F: Sodium Carbonate- Na2CO3

Sample Test 7