Hello!
The molarity of the HBr solution is 0,172 M.
Why?
The neutralization reaction between LiOH and HBr is the following:
HBr(aq) + LiOH(aq) → LiBr(aq) + H₂O(l)
To solve this exercise, we are going to apply the common titration equation:
![M1*V1=M2*V2](https://img.qammunity.org/2019/formulas/chemistry/high-school/fe54t6yr49jgovya460gf61trwxvm54sgl.png)
![M1=(M2*V2)/(V1)= (0,215 M * 37,5 mL)/(47 mL)=0,172 M](https://img.qammunity.org/2019/formulas/chemistry/high-school/tksxmaao6fbmdfhz1xzwpkjw98a43tgh0m.png)
Have a nice day!