Qualitative Analysis WAEC 2026 chemistry Practical likely Question

 

In today’s class, we are going to show you the correct analysis of what you are going to expect in this year’s WAEC chemistry practical examination based on the list of required reagents. That is why I want to encourage you to stay on this blog and enjoy the good thing it can offer you at the moment. We are also going to show one test for lead ion which you examiners do not want you to know. So, let us dive in.

 In this year’s chemistry practical, you will be presented with a mixture of two compound, organic and inorganic(lead carbonate and starch). We will be analyzing the sample with a model question below:

 

 Model Question with Answer

C is a mixture of organic and inorganic compounds. Carry out the following test, record your observation and inference in the table below:

 

S/N	Test	observation	inference
a.i	C + dilute HNO3 , filter and divide the filtrate into four portion. Keep the residue		CO2 confirmed, C is a mixture of soluble and insoluble compounds
a.ii	To the first portion from above(a.i) , add dilute NaOH in drops then excess	White precipitate soluble in excess
a.iii	To another portion, add aqueous ammonia in drops then excess		Ca2+, absent, pb2+ likely present.
a.iv	To another portion, add dilute HCl, and heat and allow cool		Pb2+ present
a.v	To another portion, add iodine solution	Yellow precipitate formed
b.i	Put the residue into a boiling tube, then add few drops of iodine solution		Starch confirmed
b.ii	To the mixture from  (b.ii), add dilute HCl and heat strongly	Blue-black colour disappears

 

Answer

 

S/N	Test	observation	inference
a.i	C + dilute HNO3 , filter and divide the filtrate into four portion. Keep the residue	Effervescence occurs, odourless, colour gas which turn blue litmus paper red and lime water milky. Partialy soluble	CO2 confirmed, C is a mixture of soluble and insoluble compounds
a.ii	To the first portion from above(a.i) , add dilute NaOH in drops then excess	White precipitate soluble in excess	Ca2+, Pb2+ likely present
a.iii	To another portion, add aqueous ammonia in drops then excess	White precipitate insoluble in excess`	Ca2+, absent, pb2+ likely present.
a.iv	To another portion, add dilute HCl, and heat and allow cool	White precipitate soluble when hot but insoluble when cool	Pb2+ present
a.v	To another portion, add iodine solution	Yellow precipitate formed	Pb2+ confirmed
b.i	Put the residue into a boiling tube, then add few drops of iodine solution	Blue-black colour formed	Starch confirmed
b.ii	To the mixture from  (b.ii), add dilute HCl and heat strongly	Blue-black colour disappears	Starch undergoes hydrolysis

 

The video is coming soon.