(A) Li+,Mg2+,Al3+ are hard acids due to high charge to size ratio.
(B) Cu+,Cd2+,Pt4+ are soft acids due to low charge to size ratio.
(C) ⊙OH,NO⊙3,CO2−3 are hard bases due to low charge to size ratio.
(D) H⊙,I⊙,CN⊙ are soft bases due to high charge to size ratio.