WAEC May/June 2024 Live Qualitative Analysis on Specimen C (a must watch)

[@bestsciencebrain]

Announcement
Final Review
As the examination is few hours from now, we make the following last review.
1. If the question states that 'C' is a mixture of two soluble salts (with the word 'soluble' emphasized in the question), then the observation and inference given in the table for question 2ai is correct as seen in the video
2. However if the question states that 'C' is a mixture of two salts (without specifying soluble) then the observation would be
Observation: C is partly soluble in water. Filtrate is colourless and residue is white.
Inference: C is a mixture of soluble and insoluble salts.
This is because it is not expected of the students to know the components of C.
3. We have already made corrections on 2aii due to the poor quality of filter paper used.
Test: Filtrate + Litmus papers
Observation: filtrate is neutral to both blue and red litmus papers
Inference: Filtrate is neutral.
Kindly stream the channel to see another video on qualitative analysis on specimen C, where the residue was treated with HNO3 instead of HCl
Good luck in your exams

[@kelechiezeorah4619]

I think HNO3 should be used on the residue instead of HCl. If Nitrate is used, lead nitrate will be formed which is soluble but if HCl is used, it will give lead chloride which is insoluble. Please, try and repeat the practical again.

[@bestsciencebrain]

Questions can be asked in different ways as you pointed out. I also repeated this experiment by adding HNO3 to the residue to solubilize it and performed test on Pb2+ using NaOH, NH3, K2CrO4 and HCl. The video is also in this channel. Kindly check for the latest video in the channel on Qualitative Analysis on Specimen C/Ultimate discussion of Alt A Practical Chemistry. Thanks

[@MAX_TV99]

Thank you so much sir God will bless you😊

[@ChiomaAnyanwu-ld3nt]

Nice work sir

[@ChiomaAnyanwu-ld3nt]

Thanks sir

[@Dave_star1]

Thank you sir

[@bestsciencebrain]

Attention Everyone
Please we observed an error in experiment No 2aii, involving filtrate with litmus papers due to poor filter paper quality used. Please take the correction below
Test: Filtrate + Litmus papers
Observation: Filtrate had no effect on both red and blue litmus papers
Inference: Filtrate is neutral.
Please effect this correction as we upload another video for a second model experiment for the same specimen C and discussions.
Thanks
Bestsciencebrain

[@AndrewJidenna]

❤❤❤ Ride on sir

[@bestsciencebrain]

Thanks

[@UchennaZebedee-qu7yc]

Good day sir.
On adding water to C, you wrote that there is a reaction that produced a white ppt. That's because you know the salts given. You know students are not supposed to know the salt given to them. They are to analyse and identify the salts. I don't think stating that reaction occurred is right because the solution will still be cloudy when water is added, if one of the two salts is soluble and the other insoluble. Assuming the original salts were lead carbonate and sodium nitrate, there Will still be cloudy solution which will not be as a result of double decomposition reaction

[@bestsciencebrain]

You made a point. We will review it. Thanks for your comment and contribution.

[@oyerindeoyeladun93]

Thanks for the tutorial, please What do you used in connecting gas to line water,

[@bestsciencebrain]

On addition of acid to the residue, effervescence occurs, quickly cover the boiling tube with a cork stopper that has already been fitted with a bent glass delivery tube. Connect the open end of the delivery tube to the cork stopper fitted to another delivery tube containing lime water. Thanks

[@bestsciencebrain]

On addition of acid to the residue, effervescence occurs, quickly cover the boiling tube with a cork stopper that has already been fitted with a bent glass delivery tube. Connect the open end of the delivery tube to the cork stopper fitted to another delivery tube containing lime water. Thanks

[@emekakoxbi7888]

Wow bro. Longest time.

[@bestsciencebrain]

Good to hear from you Bro

[@Mimi-x9h]

Keep up the good work sir.

[@bestsciencebrain]

Thanks

[@lizharrison808]

Id say using your hand to cover the top of the test tube may introduce impurities to the solution in the test tube. Its not safe. Using the stirring rod alone should be okay. Thank you for your work.

[@bestsciencebrain]

You are welcome Sir

[@lizharrison808]

Except we are told that Cn is a mixture of salts, reporting observation as "two salts mixed" may be erroneous.

[@bestsciencebrain]

Thanks

[@nwanjairuka]

Sir ,pls before writing NO3 confirmed,is it am error to first wrote NO3 present

[@bestsciencebrain]

Brown ring test completely confirms NO3^- and no other anion is suspected for such test. So there is no need to write NO3- present. Thanks for your comment

[@userIkechukwu]

You did not slant the test tube while adding conc. H2SO4.

[@bestsciencebrain]

Thanks for the observation.

[@xcott2002]

thanks sir

[@bestsciencebrain]

You are welcome

[@OgechiAbel-nm6cs]

Nice work sir Ben

[@bestsciencebrain]

Much appreciated

[@timothyadepoju8763]

❤❤❤❤❤

[@bestsciencebrain]

We appreciate

[@user-tx3rf7uv5b]

Sir how many ml do you use to dil the HCL

[@bestsciencebrain]

8 ml in 500 cm3. Thanks

[@user-tx3rf7uv5b]

@@bestsciencebrain what about the lime water

[@bestsciencebrain]

​​@@user-tx3rf7uv5b Saturate water of any volume with Calcium hydroxide. Just add calcium hydroxide to about 100 cm3 of water until large amount remained insoluble. Filter this suspension. The filtrate is your lime water. Thanks

[@user-tx3rf7uv5b]

@@bestsciencebrain thank you sir…God bless you.

[@abdulkadirabdulrahman8258]

Keep up the good work 🎉, but The filterete(NaN03) is supposed to be neutral i.e it should not have any effect on the litmus paper (it made up of strong acid HNO3 and base NaOH)

[@bestsciencebrain]

Thank you so much. We repeated this particular experiment today and we obtained a neutral solution as you pointed out. We will effect the correct in the general wall. Thanks again

[@UchennaZebedee-qu7yc]

Good day sir.
On adding water to C, you wrote that there is a reaction that produced a white ppt. That's because you know the salts given. You know students are not supposed to know the salt given to them. They are to analyse and identify the salts. I don't think stating that reaction occurred is right because the solution will still be cloudy when water is added, if one of the two salts is soluble and the other insoluble.

[@justusikennaegwuagujustusj9910]

More grease to your elbows. 👍