(/)
Visit osc-ib.com for all your IB requirements (http://osc-ib.com)
OVER 3 ,5 0 0 IB BL OGS FOR STU D EN TS AN D TEAC H ER S; WR ITTEN BY EXPER TS. N EW BL OGS EVER Y MON D AY, WED N ESD AY AN D FR ID AY!
By David Allen (https://blogs.osc-ib.com/author/triplea_da/)
Monday, March 22, 2010
The IB Climb
Chemistry
(https://blogs.osc-ib.com/ib-blogs/ib-teacher-blogs/dp_chemistry/), IBDP Teacher Blogs (https://blogs.osc-ib.com/ib-
(https://blogs.osc-ib.com/2016/01/ib-
blogs/ib-teacher-blogs/)
student-blogs/the-ib-climb/)
alcohol (https://blogs.osc-ib.com/tag/alcohol/), fehlings (https://blogs.osc-
ib.com/tag/fehlings/), oxidation (https://blogs.osc-ib.com/tag/oxidation/), primary (https://blogs.osc-ib.com/tag/primary/),
Facing IB exams with confidence
secondary (https://blogs.osc-ib.com/tag/secondary/)
(https://blogs.osc-ib.com/2016/01/ib-
7
student-blogs/facing-ib-exams-withconfidence/) Revise Review Remember (https://blogs.osc-ib.com/2016/01/ibstudent-blogs/revise-reviewremember/) What to do if your IB results are below expectations (https://blogs.osc-ib.com/2016/01/ib-
(https://blogs.osc-ib.com/2010/03/ib-teacher-blogs/dp_chemistry/potassium-dichromatetests-for-primary-secondary-and-tertiary-alcohols/)
student-blogs/what-to-do-if-your-ibresults-are-below-expectations/)
(http://www.addthis.com/bookmark.php?v=250&username=xa-
Proper Planning Prevents Poor
4ba158854284eb75)
Performance
Here are some ideas for some easy test tube reactions that cover redox, intermolecular
(https://blogs.osc-ib.com/2016/01/ib-
forces, alcohols, ketones, aldehydes, carboxylic acids and chemical tests.
student-blogs/proper-planningprevents-poor-performance/)
We can use acidified potassium dichromate (K2Cr2O7) solution to distinguish between
Planning for IB success
primary, secondary and tertiary alcohols.
(https://blogs.osc-ib.com/2016/01/ib-
As with all the experiments listed on this website,
student-blogs/planning-for-ib-
specific experimental details are not given.
success/) Making the grade – revising English
It is your responsibility to research each method and to carry out a substantial risk
A and Language B subjects
analysis.
(https://blogs.osc-ib.com/2016/01/ib-
Primary alcohols are oxidised to aldehydes and the carboxylic acids
student-blogs/making-the-grade-
Secondary alcohols are oxidised to ketones.
revising-english-a-and-language-b-
Tertiary alcohols cannot be oxidised by the dichromate ions.
subjects/) Five Top Physics Tips
Dichromate ions (Cr2O7 2-) are orange. On reduction Cr 3+ ions are formed which are green.
(https://blogs.osc-ib.com/2016/01/ib-
student-blogs/five-top-physics-tips/) Five Top Maths Tips
Can you write a half equation to show this (Hint: The dichromate solution is acidified).
(https://blogs.osc-ib.com/2016/01/ib-
So you would expect to see the tertiary alcohol remaining an orange colour whilst the
student-blogs/five-top-maths-tips/)
secondary and tertiary alcohols would be oxidised and in doing so, the dichromate ions
Extended Essay research – reading
would be reduced to give a green solution.
between the lines
To distinguish between primary and secondary alcohols you would use either Tollen’s
(https://blogs.osc-ib.com/2016/01/ib-
reagent or Fehlings solution.
student-blogs/extended-essay-
The unknown alcohol would first need to be oxidised to either the ketone or the aldehyde.
research-reading-between-the-lines/)
Tollens or Fehlings would be added. Aldehydes will react. Ketones will not react.
An IB student’s New Year’s resolution
For Tollens reagent, a positive result produces a Silver mirror.
(https://blogs.osc-ib.com/2016/01/ibstudent-blogs/an-ib-students-newyears-resolution/) Engage your brain…use it or lose it! (https://blogs.osc-ib.com/2016/01/ibstudent-blogs/engage-your-brainuse-it-or-lose-it/) ‘The summer of the Extended Essay’ – easy tips to get you ahead (https://blogs.osc-ib.com/2016/01/ibstudent-blogs/the-summer-of-theextended-essay-easy-tips-to-getyou-ahead-2/) Why we need sleep (https://blogs.osc-ib.com/2016/01/ib-
student-blogs/why-we-need-sleep/)
For Fehlings solution, the liquid turns from a deep transparent blue colour to a brick red
Choosing your IB Subjects: Don’t
precipitate. The clip mentions that Glucose is added to Fehlings – this is because Glucose
Panic!
has an aldehyde group!
(https://blogs.osc-ib.com/2016/01/ibstudent-blogs/choosing-your-ibsubjects-dont-panic/) Before you start the IB Diploma, think about your University Choices (https://blogs.osc-ib.com/2016/01/ibstudent-blogs/before-you-start-the-ibdiploma-think-about-your-universitychoices/) Magical Revision Tips. Part 4. (https://blogs.osc-ib.com/2016/01/ibstudent-blogs/magical-revision-tipspart-4/) Magical Revision Tips. Part 3. (https://blogs.osc-ib.com/2016/01/ibstudent-blogs/magical-revision-tipspart-3/) Magical Revision Tips. Part 2. (https://blogs.osc-ib.com/2016/01/ib-
(https://blogs.osc-ib.com/wp-content/uploads/2010/03/800px-Fehling_test1.png)
student-blogs/magical-revision-tips-
How could you ensure that a primary alcohol is not further oxidised to a carboxylic acid?
part-2/) Magical Revision Tips. Part 1.
You would carry out the reaction by warming and collecting the vapour using a Lieberg
(https://blogs.osc-ib.com/2016/01/ib-
condenser.
student-blogs/magical-revision-tipspart-1/)
Goodbye NAVIANCE: What next? Alternative Platforms for International Schools (https://blogs.oscib.com/2018/05/ib-teacherblogs/goodbye-naviance-what-nextThe primary alcohol will have a relatively high boiling point due to hydrogen bonds but the
alternative-platforms-for-
aldehyde only has dipole – dipole forces so it will evaporate / boil at a much lower
international-schools/)
temperature.
Migration from Venezuela (https://blogs.osc-ib.com/2018/05/ib-
If you wanted to form the carboxylic acid you would need to reflux the mixture of primary
teacher-
alcohol and dichromate.
blogs/dp_geography/migration-fromvenezuela/) The Maths Behind Record Breaking (https://blogs.osc-ib.com/2018/05/ibstudent-blogs/the-maths-behindrecord-breaking/) Inward Investment in Senegal (https://blogs.osc-ib.com/2018/05/ibstudent-blogs/inward-investment-insenegal/)
Get our free email alerts on the topics and author of this article:
(https://www.facebook.com/OxfordStudyCourses)
3 Chemistry
Get Free Alerts
Enter email address...
powered by followistic
(https://twitter.com/OSC_IB) (https://www.linkedin.com/company/oxfordstudy-courses-ltd)
1. Reactions of the Haloalkanes and Testing for Halide Ions (https://blogs.oscib.com/2010/03/ib-teacher-blogs/dp_chemistry/reactions-of-the-haloalkanes-andtesting-for-halide-ions/)
(https://instagram.com/oxfordstudycourses/)
2. Ageing Wine (https://blogs.osc-ib.com/2010/07/ib-teacherblogs/dp_chemistry/ageing-wine/)
(https://www.youtube.com/user/OxfordStudyCourses)
3. Alcohol / Ethanol (https://blogs.osc-ib.com/2010/09/ib-teacherblogs/dp_chemistry/alcohol-ethanol/) 4. Top Tips for Success (3) (https://blogs.osc-ib.com/2012/03/ib-teacherblogs/dp_chemistry/top-tips-for-success-3/)
(http://www.facebook.com/sharer.php? (http://twitter.com/share? (https://plus.google.com/share? (http://www.linkedin.com/shareArticle? (mailto:? u=https://blogs.oscurl=https://blogs.oscurl=https://blogs.oscmini=true&url=https://blogs.oscSubject=Potassium%20dichromate%20Tests%20for%20Primary,%20Secondary%20and%20Tertiary%20Alcohols&Body=https://blogs.osc-
New Geography blog post for IB
ib.com/2010/03/ibib.com/2010/03/ibib.com/2010/03/ibib.com/2010/03/ibib.com/2010/03/ib-
blogs/dp_chemistry/potassiumblogs/dp_chemistry/potassiumblogs/dp_chemistry/potassiumblogs/dp_chemistry/potassiumblogs/dp_chemistry/potassium-
Next Post » (https://blogs.osc-ib.com/2010/03/ib-teacher-blogs/dp_biology/earth-day-and-the-precautionary-principle/) dichromatedichromatedichromatedichromatedichromatetestsfor-
Ahmed
testsfor-
testsfor-
testsfor-
testsfor-
primary- primary- primary- primary- primary-
June 2, 2011 secondarysecondarysecondarysecondarysecondary-
Thanks that was useful
and-
and-
and-
and-
note:i thought its a liebig not lieberg condenser .
Explore and create in a fresh and
students: Migration from Venezuela. Congratulations on making it through vibrant setting this Summer on
teacher- teacher- teacher- teacher- teacher« Previous post (https://blogs.osc-ib.com/2010/03/ib-teacher-blogs/dp_chemistry/accurate-or-precise-whats-the-
difference/)
The IB exams are over!
and-
tertiary- tertiary- tertiary- tertiary- tertiary-
Reply
https://t.co/Lxk6Um62aY
this tough time! Now, go relax and
OSC's Visaul Arts course in
(https://t.co/Lxk6Um62aY) #ibdp
enjoy your summer. D…
Tuscany.…
(http://twitter.com/search?
https://t.co/l7E9P5XDhb
https://t.co/bvk8vw6RW2
q=%23ibdp) #ibgeography
(https://t.co/l7E9P5XDhb)
(https://t.co/bvk8vw6RW2)
(http://twitter.com/search?
Reply (https://twitter.com/intent/tweet?
Reply (https://twitter.com/intent/tweet?
q=%23ibgeography)
in_reply_to=997809335647571968)
in_reply_to=997771428991729665)
Reply (https://twitter.com/intent/tweet?
Retweet
Retweet
in_reply_to=998488754280116224)
(https://twitter.com/intent/retweet?
(https://twitter.com/intent/retweet?
Retweet
tweet_id=997809335647571968)
tweet_id=997771428991729665)
(https://twitter.com/intent/retweet?
Favorite
Favorite
tweet_id=998488754280116224)
(https://twitter.com/intent/favorite?
(https://twitter.com/intent/favorite?
Favorite Search
tweet_id=997809335647571968)
tweet_id=997771428991729665)
(https://twitter.com/intent/favorite?
19 May 2018
19 May 2018
alcohols/)alcohols/&text=Potassium%20dichromate%20Tests%20for%20Primary,%20Secondary%20and%20Tertiary%20Alcohols) alcohols/)alcohols/)alcohols/)
tweet_id=998488754280116224)
(https://twitter.com/OSC_IB/status/997809335647571968) (https://twitter.com/OSC_IB/status/99
21 May 2018
lalo
(https://twitter.com/OSC_IB/status/998488754280116224)
January 5, 2014 how far does the potassium dichromate detect alcohol (timewise)in a breath test of a .02? Reply
lalo January 5, 2014 im referring about the reditest alcohol breath test Reply
anan February 27, 2016 Wouldn’t acidified potassium dichromate, being a strong oxidising agent ,oxidise the primary alcohol to carboxylic acid before you get the chance to test for the aldehyde? Reply
triplea_da March 5, 2016 Hi Anan, Yes, this is correct. However, if you wish to obtain the aldehyde you can distill it, otherwise you can reflux to obtain the acid. All the best, Dave Reply
Your email address will not be published. Required fields are marked * Comment
Name *
Email *
Website
CAPTCHA Code
*
Post Comment
Privacy Policy (http://blogs.osc-ib.com/privacy-policy/) | About OSC (http://blogs.oscib.com/about-osc-blogs/) | Contact (http://blogs.osc-ib.com/contact-us/) Copyright OSC © 1998-2017 e:
[email protected] (mailto:
[email protected]?subject=OSC Blog Query) t: