Terylene (repeat unit $C X_{10} H X_{8} O X_{4}$ , 192) of mass 960 g is made by the dimethyl terephthalate route from dimethyl terephthalate and ethylene glycol (end groups ignored; $CH X_{3} OH$ = 32). The mass of methanol released in grams is

Answer: A

960 g corresponds to

960/192 = 5.00

repeat units (mol). Each repeat unit forms two ester links by exchange of two

- OCH X_{3}

groups, so

10.0

mol of methanol is released. Mass

= 10.0 \times 32 = 320

g; the value

180

g would be water.