Question

If 5.25 mL of a 0.278 M solution of NaOH is required to neutralize 15.7 mL of a HCl solution, What is the concentration of the HCl solution?

Select one:

a. 15 M

b. .450 M

c. 0.0930 M

d. 0.555 M

Answer 1

NaOH reacts with HCl and produces H₂O and NaCl.
The balanced reaction is :
NaOH + HCl ----> NaCl + H₂O

Therefore, 1 mol of NaOH reacts with 1 mol of HCl.

No. of mol of NaOH = molarity x volume in L
                   = 0.278 mol/L x 0.00525 L
                   = 1.4595 x 10-3 mol
                 
Therefore, we need 1.4595 x 10^-3 mol of HCl to neutralize the NaOH.

Molarity = no. of mol/ volume in L
       = 1.4595 x 10^-3 mol / 0.0157 L
       = 0.0930 mol/L
       = 0.0930 M
Hence, the molarity of HCl = 0.0930.
Answer = C(0.0930 M)