<u>Answer:</u> The additional information that is helpful in calculating the mole percent of XCl(s) and ZCl(s) is the molar masses of Z and X
<u>Explanation:</u>
To calculate the mole percent of a substance, we use the equation:

Mass percent means that the mass of a substance is present in 100 grams of mixture
To calculate the number of moles, we use the equation:

We require the molar masses of Z and X to calculate the mole percent of Z and X respectively
Hence, the additional information that is helpful in calculating the mole percent of XCl(s) and ZCl(s) is the molar masses of Z and X
condensation polymerization, since a byproduct of the reaction is a single molecule of water (hence condensation of water)
addition polymerization is if you add the two polymers together like blocks and should have no byproducts
esterification is when you combine an organic acid with an alcohol. Since neither of the two polymers look like acids, you can rule this out.
never heard of saponification, Im an mechanical engineer not an organic chemist
Answer: D.
Explanation: A chemical reaction is said to be in a state of equilibrium when the rate of the forward reaction equals the rate of the backward reaction, thus, there is no net change in the concentration of reactants and products.