Question

The ester below can be separated into phenol and an acetate salt, via saponification: heating the ester with a strong base, such as sodium hydroxide, will produce phenol and sodium acetate. the two chemicals can then be separated by heat and filtration.
a. calculate the unsaturation number of the ester above.
b. calculate the molecular weight of the ester above

Answer 1

I found a similar question online which will help me answer your incomplete question. To make it easier, show all the elements of the compound given. It is shown in the second picture attached.

a.) The formula for unsaturation number is shown in the 3rd picture attached. Following this, 
n = 8
m = 2(8) + 2 + 0 + 0 - 0 = 18
Thus,
x = Unsaturation number = (18 - 8)/2 = 5
The unsaturation number is 5.

b.) The molar mass of C is 12.01 g/mol; H is 1 g/mol; O is 16 g/mol. So, the molecular weight is:
Molecular weight = 12.01(8) + 8(1) + 2(16) = 136.08 g/mol
The molecular weight of the ester is 136.08 g/mol.