Scientists originally believed that mercury could only be absorbed when it existed in an
aqueous solution. Which of the following solutions would render the mercury solution
safe under this assumption?
a. CaCO 3
b. Ba 3 (PO 4 ) 2
c. NaCl
d. PbCl 2
e. None of these

The characteristic of two different types of reactions are shown below. reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of and element. which statement is true about the atoms of the elements that participate in the two reactions? a: their identity changes in both reaction a and b. b: their identity changes in reaction a but not b. c: their identity changes in reaction b but not a. d: their identity remains the same.