Good question. I'm not sure.

a sterically hidered base is a big, crowded base. It is so big, that it can only get to hydrogens that have a lot of space around them. For instance, hydrogens on a primary C have more space around them than hydrogens on a secondary C. Therefore a bulky base will take primary H's instead of secodary H's

The 2D pictures were made using chem draw. The 3D pictures were made using arguslab, which is an incredible shareware program for molecular modelling. The molecules were saved in XYZ format, and then opened and manipulated in JMOL, which is also freely available.

@@rickpires5156 thanks for your reply...I will try to Get it done.

This was part of a "lab activity" for my students during the pandemic when we couldn't meet. I was really desperate (we weren't allowed in our building to so I couldn't make my own video) so I did what I could. Pathetic, I know.

@@rickpires5156 than at least give credit to the original creator of the video or just send your students a link to the original video

@@rickpires5156 Not pathetic at all! My Orgo lab professor does the same thing and her dubbing over it helps a lot. You did great!

@@alyssamercier6459 Thank you.

trans 1,3 dichlorocyclobutane has a center of symmetry, but trans 1,2 dichlorocyclobutane does not

@@rickpires5156 sir why not....I cannot understand this concept clearly.... please make a animated video on center of symmetry.... please sir....it's my hearty request.... please sir... please.... I'm waiting for your video

@@syedsahadatali7005 I'll see if I can, but I'm not sure if I can. Because of COVID-19 I can't get into my office where all of my software is.

Sir u have really done a good work... Plzz keep uploading videos

Hi Alec!

also the "in 15 min" *"about 10 min later"* love pires

optical purity =[ (observed rotation)/(reference value)] x100 (reference value is the value you look up for the compound, observed value is what you measured in lab) percent major isomer = 50 + (optical purity)/2

Jmol is hard to draw structures with, so structures were drawn with another program (arguslab- a great freeware program) then saved in XYZ format. The molecules were displayed and manipulated using Jmol during the videos

lol, you wrong for that

The major product would be the same, but for a different reason. LiAlH4 is much more exothermic. For very exothermic reactions, usually the transition state matters less in product distribution, and the product stability matters more. So in this case, the trans substituted product is favored because of the stability of the product.

@@rickpires5156 Thank you so very much. I couldn't find this solution anywhere else....... Thank you

The 3d molecules themselves were drawn with arguslab, which is the greatest freeware program ever. The molecules were opened in jmol and the planes of symmetry were drawn with jmol. Arguslab is easy to use. jmol is more complicated (there are an incredible amount of different things you can do with it), but I've got a guide that I've written that specifies just the things I need for these models

The molecules were drawn in a freeware program called arguslab, and then imported into a program called jmol (also free) to draw the planes of symmetry. In jmol, use 3 dummy atoms to define the plane of symmetry, and once the plane is drawn, hide the dummy atoms

With 3d visualisation

trans 1,2-dichloropropane does not have a plane of symmetry and is chiral. Cis 1,2 dichloropropane does have a plane of symmetry and is not chiral

Ok thanks 😍 Can i send any other questions if i find problem about subject called optical activity ??! 😅

My problems about How to detect the specific rotation of enatiomers 😅

@@kerollosnabil2533 yes

@@kerollosnabil2533 You cannot look at a molecule and tell what its specific rotation will be just by seeing which enantiomer you have. Specific rotation has to be measured in the lab on a piece of equipment called a polarimeter

You can use the clip. What do you want to talk about?