What's the answer to this question? Steps?

Question

A 20.0 mL sample of ammonia was titrated with 12.6 mL of 0.25 mol/L HCl. What was the initial concentration of the ammonia?

A) 0.16mol/L

B) 0.097mol/L

C) 0.25mol/L

D) none of these

Answer 1

M₁V₁ = M₂V₂

remember, M = mol/L

convert both mL to L by dividing by 1000

20.0 ml/1000 ml = 0.020 L

12.6 ml/1000 ml = 0.0126 L

M₁(0.020 L) = (0.25 M)(0.0126 L) = 0.16M