4. How much water should be added to 50 mL of 12 M hydrochloric acid to produce a 4.0 M solution?

Answer 1

This sounds like a dilution problem. To do this, we can use the dilution equation:

c₁v₁=c₂v₂ ,

where c = concentration and V= volume.

Using this equation, we know that we have 50mL of a solution with a concentration of 12M. We can assign these as v₁ and c₁, respectively. Since we want to make a solution with a concentration of 4M, we know that c₂=4M.

Rearranging c₁v₁=c₂v₂ to solve for v₂, the total volume of our 4M solution, we have:

(c₁v₁/c₂)=v₂

∴(12M)(50mL)/(4M) = v₂ = 150 mL

Since we know that 150mL will be the total volume at the end of our dilution, we can deduce that 100mL of water must be added to the 50mL initial solution.