Answer: The number of moles of sodium hydroxide required to reach the endpoint is 0.00128 
Step-by-step explanation:
To calculate the number of moles for given molarity, we use the equation: 
 
 
Molarity of 
 solution = 0.100 M
 solution = 0.100 M 
Volume of 
 solution = 12.8 mL
 solution = 12.8 mL 
Putting values in equation, we get: 

Thus the number of moles of sodium hydroxide required to reach the endpoint is 0.00128