Question

Please help: A 0.200 M NaOH solution was used to titrate a 18.25 mL HF

solution. The endpoint was reached after 31.20 mL of titrant
were added. Find the molar concentration of the original HF
solution.

Answer 1

The molar concentration of the original HF solution : 0.342 M

Further explanation

Given

31.2 ml of 0.200 M NaOH

18.2 ml of HF

Required

The molar concentration of HF

Solution

Titration formula

M₁V₁n₁=M₂V₂n₂

n=acid/base valence (amount of H⁺/OH⁻, for NaOH and HF n =1)

Titrant = NaOH(1)

Titrate = HF(2)

Input the value :

`\tt 0.2* 31.2* 1=M_2* 18.25* 1\\\\M_2=0.342`