Use the table and answer these questions.
a) The student says that measuring pH alone is not enough to measure the purity of a water sample. Give evidence from the table that supports this statement
b)sample C has no solid residue left when evaporated. Suggest why it has a boiling point 1.7 degrees lower than distilled water
c) The solid residue in samples A and B is found to be sodium chloride. Explain why samples A and B conduct electricity but distilled water does not.