Out of H2SO4(I), H2S2O7(II), H2SO5(III) and H2S2O3(IV):
Column-I-Compound, Column-II-Oxidation state, Column-III-Type of linkage
Column 1Column 2Column 3(I)Na2S2O3(i)+5(P)S−O−S(II)Na2S4O6(ii)−2(Q)S−S(III)H2S2O7(iii)+6(R)−(O−O)−(IV)H2S2O8(iv)+4(S)S=S
The only correct combination for Marshall’s acid: