[punky]

today in class they were discussing how they made soap 100 years ago..is there a better way to understand what exactly they do to make soap?  

[hmx9123]

There's a really excellent thread on soapmaking in the Old Forums:

http://www.chemicalforums.com/index.php?board=17;action=display;threadid=219

[jdurg]

I found from my experience that the stronger the base you use when making soap, the more liquid your end product is.  I think if you tried making soap with RbOH or CsOH it wouldn't even be a soap anymore.  

[jkrumh1]

It probably wouldn't be even safe to use as soap.
At least i think...

[hmx9123]

I have read that if you use the Na salt, you get solid soap, but using K, you get liquid soap.  I haven't read about Rb or Cs, although I doubt that the salts are very toxic.  You probably wouldn't wind up with something that looks like what we normally consider soap, though.

[jdurg]

Rubidium and cesium salts are not toxic, to my knowledge.  It's just that the strength of the base increases as you move down the alkali metal group.  I believe that KOH is able to break down the fatty acid chains much better than NaOH, thus causing the soap that forms to be liquid.  As you move down to RbOH and CsOH, the base is so strong that I'm pretty sure that a saponification reaction won't happen as the organic molecule would be destroyed by some other mechanism.