Molar mass of H3PO4 = 98 gm/mol
% composition = Atomic mass Molecular mass ×100%
%H=3×1⋅g⋅mol−198⋅g⋅mol−1×100%=3.1%
%P=31⋅g⋅mol−198⋅g⋅mol−1×100%=31.6%
%O=4×16⋅g⋅mol−198⋅g⋅mol−1×100%=65.3%
(i) What is the mass number of X ?
(ii) What is the mass number of Y ?
(iii) What is the relation between X and Y ?
(iv) Which element/elements do they represent ?