Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Join your school's WhatsApp group

2019 WAEC Chemistry Practical All your burette readings (initials and final), as well as the size of your pipette, must be...

Chemistry
WAEC 2019

All your burette readings (initials and final), as well as the size of your pipette, must be recorded but no account of experimental procedure is required. All calculations must be done in your answer booklet.

(a) State what would be observed when \(BaCl_2\) solution is a portion of a saturated Na\(_2\)CO\(_2\) followed by dilute HCI in excess.

(ii) A gas Q decolorized acidified kMnO\(_4\) Solution. Suggest what Q could be

 

(b) Name one substance used in the laboratory for drying each of the following substances:

(i) ammonia gas:

(ii) carbon (IV) oxide. 

 

(c) Give a reason why a given mass of sodium hydroxide pellets cannot be used to prepare a standard solution. 

Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Join your school's WhatsApp group
NECO June/July 2024 - Get offline past questions & answers - Download objective & theory, all in one app 48789
Explanation

(a) BaCl\(_{2(aq)}\) +  Na\(_2\)CO\(_{3(aq)}\) followed saturated by dilute HCl in excess

- A white precipitate is formed.

- Effervescence occurs and a gas evolved and the white precipitate dissolves in excess dil HCl

(ii) Gas Q that decolourized acidified KMnO\(_2\) solution could be any of these.

SO\(_{2(g)}\), H\(_2\)S\(_{(g)}\), unsaturated hydrocarbon (C\(_2\)H\(_{2}\), C\(_2\)H\(_4\)....)

 

(b) One substance used in the laboratory for drying each of the following:

(I) ammonia gas - Calcium oxide

(ii) carbon (IV) Oxide - Calcium chloride

- Concentrated tetraoxosulphate( VI) acid.

 

(c) Sodium hydroxide pellets cannot be used to prepare a standard solution because it is deliquescent, it absorbs water vapour (moisture) and carbon (IV) oxide from the air, and this would add to its mass.


Report an Error Ask A Question Download App
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
NECO June/July 2024 - Get offline past questions & answers - Download objective & theory, all in one app 48789

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 Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Join your school's WhatsApp group
NECO June/July 2024 - Get offline past questions & answers - Download objective & theory, all in one app 48789
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
NECO June/July 2024 - Get offline past questions & answers - Download objective & theory, all in one app 48789
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
Join your school's WhatsApp group