Answer to Question #253320 in Chemistry for Rahima

Question

1. 85.0 mL of a solution of NaOH is diluted to a final volume of 290.0 mL and the new molarity is 0.0500 M. Calculate the original molarity of the base. 

M1*V1= M2*V2

Answer 1

c₁ = unknown

V₁ = 85.0 mL

c₂ = 0.0500 M

V₂ = 290.0 mL

Solution:

The equation for dilution calculations can be used

where:

c₁, V₁ - the molarity and volume of the concentrated solution

c₂, V₂ - the molarity and volume of the diluted solution

 

Thus:

c₁ × (85.0 mL) = (0.0500 M) × (290.0 mL)

c₁ = (0.0500 M × 290.0 mL) / (85.0 mL) = 0.1706 M = 0.171 M

c₁ = 0.171 M

Answer: The original molarity of the base is 0.171 M