Table: phosphoric_acid_concentrations
Columns: a_mol_l
ph
h_3_po_4_a
h_2_po_4_a
hpo_4_2_a
po_4_3_a

Question: what is [po 4 3− ]/[a] (%) where [h 2 po 4 − ]/[a] (%) is 94.5?
SQL: SELECT "po_4_3_a" FROM phosphoric_acid_concentrations WHERE "h_2_po_4_a" = '94.5'

Question: what is the [a] (mol/l) where [hpo 4 2− ]/[a] (%) is 0.612?
SQL: SELECT COUNT("a_mol_l") FROM phosphoric_acid_concentrations WHERE "hpo_4_2_a" = '0.612'