The equation that you need to use is M₁V₁=M₂V₂ for both cases since the molar ratio is 1.
In titration 1: You would use the equation M₂=M₁V₁/V₂
M₁=concentration of NaOH (0.1M) V₁=volume of NaOH added (16mL) V₂=volume of HCl in the Erlenmeyer flask (20mL) M₂=concentration of HCl in the Erlenmeyer flask (unknown)
M₂=(0.1M*16mL)/20mL M₂=0.08M The concentration of acid was 0.08M
Titration 2: Still use the formula M₂=M₁V₁/V₂
M₁=concentration of HCL (0.1M) V₁=volume of HCl added (14mL) V₂=volume of NaOH in Erlenmeyer flask (20mL) M₂=concentration of NaOH in the Erlenmeyer flask (unknown)
M₂=(0.1M*14mL)/20mL M₂=0.07M concentration of the NaOH is 0.07M
I hope this helps. Let me know if you have any further questions or if anything needs to be clarified.
