Brian Ducille That's very kind of you to say so Brian. It's great to hear that the videos are helping fellow teachers as well as students. I'll be making more next year for the new specification so keep watching. Thanks again :)

Sonil Zaki You did with your positive comment :)

Very kind of you to say so. Glad the videos help!

Brian Ducille Hi Brian, many thanks for your feedback. I'm glad you have found the videos useful. Can I just ask I what capacity do you use them? Are you a teacher by any chance? If so, do you work in a UK school and teach A level Chemistry? I'm compiling a report for my Principal as to the impact of the videos and your answers to these questions would be very helpful. Thanks in advance.

Lumar Lucena You're welcome. Thank YOU very much

Mustafa Aminalhaq Thanks for that. Glad you think so

@@MaChemGuy sir this is such a great, top tier video, thank you. 🤩

Chuffed it helped you. Thanks for letting me know 😊

Glad I’m able to help

how'd it go

The SP in the question was a liquid alkane and so non polar. Interactions will therefore be via van der Waals forces not H-bonds. The more H-bonding potential, the less interaction and so shorter RT. If the SP had been polar however, it would have had the longest RT. It all depends on the nature of the SP

For a substance to dissolve in another substance they need to be able to interact with each other. Polar molecules dissolve each other by dipole dipole or hydrogen bond interactions and non polar by van der Waals interactions. Just remember 'like dissolves like'

Firmino Becker Where does it break down for you. I’ll try and explain it in a different way for you

Have you come across the 'like dissolves like' phrase for solubility? Non-polar molecules dissolve/interact with the non-polar stationary phase by forming van-der Waals forces with it. Polar molecules can't do that as they interact by forming hydrogen bonds. Does that help?

Forgot to say that the greater the interaction the longer it takes for the molecule to travel through the column

+MaChemGuy So non-polar molecules will be slowed down the most? Thank you so much! I watch your videos on a daily basis :)

+Alexxx Exactly! And if the stationary phase was polar, it would be the other way round. Glad you find them helpful :)

Alexxx hi

i myself dont know why, but it may change the factor of which affects interactivity when it is a longer chain.

with the stationary phase, that is

Day dreamer Xxx The stationary phase isn’t water, it’s a liquid alkane. Like dissolves like so the alkane will dissolve best into it due to its ability to form vdw with it. The alcohol will interact the least as it can’t form H bonds with an alkane

cutiee pie Glad you liked it and thanks!

Alastair Grundy When he says they form hydrogen bonds, he means between molecules of themselves, not between the alcohols and the stationary phase. The liquid stationary phase (say a long chain alkane) is not capable of hydrogen bonding, so cannot effectively dissolve the alcohols. Remember 'Like dissolves like'. In this case, it's not so much about the strength of the different interactions but whether or not they are present. If the stationary phase was a substance capable of hydrogen bonding then the order would reverse.

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