Addition of citric acid to metal ion solution makes
the solution viscous with no precipitation or agglomeration
of ions from the homogeneous solution.
Citric acid is used as a fuel for combustion
as well as it forms a polymer matrix, which
avoids the precipitation of ions. When the gel
undergoes decomposition it forms a fluffy mass
which indicates the evolution of CO2 due to the
decomposition of citric acid and the organic constituents
of eggshell