Answer:
it is probably acrylic or latex
Explanation:
HCl(aq) + KOH(s) --> KCl(aq) + H2O(l)
Eggshells are made primarily of calcium carbonate. The acid in vinegar softens the calcium of the eggshell. Adding a little vinegar to the water when boiling eggs is an old cook’s trick that makes them easier to peel.
A link to this experiment is below in the comment box
He thought elements that haven't been discovered belonged in the place of the gap. He could also use the atomic mass of the missing elements