Answer:
0.058 M
Step-by-step explanation:
HBr reacts with NaOH and forms NaBr and H₂O as the products. The balanced equation is as follows:
![NaOH + HBr \implies NaBr + H_2O](https://img.qammunity.org/2020/formulas/chemistry/middle-school/xc19ay6bi8jceqvy9glj1omtck696bwvmb.png)
Molarity (M) = moles of solute (mol) / volume of the solution (L)
Molarity of NaOH = 0.115 M
Volume of NaOH = 18.2 mL = 18.2 x 10⁻³ L
So, moles of NaOH = molarity x volume of the solution
= 0.115 M x 18.2 x 10⁻³ L
= 2.093 x 10⁻³ mol
From the equation, we can see that the ratio between NaOH and HBr is 1 : 1.
Therefore, moles of HBr in 35.6 mL = moles of NaOH added = 2.093 x 10⁻³ mol
Hence, molarity of HBr = 2.093 x 10⁻³ mol / 35.6 x 10⁻³ L = 0.058 M