WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts

2024 WAEC Chemistry Practical (a) An aqueous solution of a salt was added to excess sodium sodium trioxocarbonate (IV) solution...

Chemistry
WAEC 2024

(a) An aqueous solution of a salt was added to excess sodium sodium trioxocarbonate (IV) solution in a test tube. There was effervescence, the test tube became warm and a white precipitate was observed. State three inferences that could be drawn from these observations.

(b) Consider the following salts; NH\(_4\)Cl; PbSO\(_4\); NaHCO\(_3\) and Cu(NO\(_3\))\(_2\).

  Select from the list, the salt(s) which:

(i) would not readily dissolve in water;

(ii)produce(s) effervescence with dilute mineral acids;

(iii) decompose(s) on heating;

(iv) dissolve(s) in water to form an alkaline solution;

(v) sublime(s) on heating

(c)  A solution of an acid was titrated with sodium hydroxide solution using methylorange as the indicator. State three precautions that are necessary when carrying out such an experiment.

WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Explanation

a(i) Salt solution is acidic

     - Reaction is exothermic.

    - White precipitate is likely to be a trioxocarbonate(IV) salt of Al, Ca and Zn.

    - Prepared solution contained soluble salt of Al, Ca and Zn.       

b(i)PbSO\(_4\)

  (ii) NaHCO\(_3\)

  (iii) NaHCO\(_3\) ; Cu(NO\(_3\))\(_2\).

  (iv) NaHCO\(_3\)

  (v) NH\(_4\)Cl

(c) Precautions to be taken during titration include:

- Wear a lab coat to protect your clothing from spills. 

- Ensure to rinse the burette with an acid solution

- Also ensure the funnel is removed immediately after filling the acid into the burette.

- Avoid error due to parallax while taking the reading to determine the end point.

- Ensure all glassware is clean and free of bubbles. 


Report an Error Ask A Question Download App
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076

Contributions ({{ comment_count }})

Please wait...

{{ settings.no_comment_msg ? settings.no_comment_msg : 'There are no comments' }}

Quick Questions

Post your Contribution

Please don't post or ask to join a "Group" or "Whatsapp Group" as a comment. It will be deleted. To join or start a group, please click here

{{ quote.posted_by.display_name }}
{{ settings.form_textarea_description }}
 
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC offline past questions - with all answers and explanations in one app - Download for free
Post UTME Past Questions Agent
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 127076
Post UTME Past Questions Agent