Sorting slides.

[#1]

Can I use Exif (Exchangeable image file format) to sort scans of my  photo slides?
I have several thousand slides that I have scanned in to my pc.
Will the date taken information be within the slide or will the date I scanned the slide
be what is captured by Exif?
If it is the latter, is there any software/method that I can use to sort the slides by date taken?
Thank you

[#2]

I would think it highly unlikely that the camera used to take the slides would have date facility and transparency film doesn't have such a facility.
Therefore the date on the scanned image will be the scan date.

[#3]

Exif data is meta-data and only gets stored for digital images.
You can extract copious exif data if you have it.
Otherwise, there are programs that allow you to store keyword(s) against each photo.
Personally, I store each batch of photos in a directory called YYYY-MM-DD_descriptive_name
BTW Many images on web sites still contain all their exif data - which reveals all sorts of info (possibly including GPS coordinates).