Who first published the classification of the elements

Achemistry student weighs out of phosphoric acid , a triprotic acid, into a volumetric flask and dilutes to the mark with distilled water. he plans to titrate the acid with solution. calculate the volume of solution the student will need to add to reach the final equivalence point. round your answer to significant digits.

If two atoms are bonded to a central atom with no lone pairs, how will they be arranged

Answer explain why it is not possible to deduce a complete order of reactivity.