which of the following types of machine guard is generally preferred because of its simplicity and durability? A) interlocked B) fixed C) self adjusting D) adjustable In the separation of fluorene and...

which of the following types of machine guard is generally preferred because of its simplicity and durability? A) interlocked B) fixed C) self adjusting D) adjustable

In the separation of fluorene and fluorenone by column chromatography, what is the stationary phase? the mobile phase?