Question

How many ounces of pure hydrochloric acid should be added to 20 mL of a 30% solution to obtain a 50% solution?

Answer 1

To calculate the amount of pure hydrochloric acid to add to a 20 mL, 30% solution to achieve a 50% solution, we use the formula C1V1 = C2V2 and solve for x, which will be converted from milliliters to ounces.

Step-by-step explanation:

To determine how many ounces of pure hydrochloric acid should be added to 20 mL of a 30% solution to obtain a 50% solution, we need to use a concentration formula: C1V1 = C2V2, where C represents concentration and V represents volume.

Let's assume we're adding x ounces of pure hydrochloric acid (100% concentration) to the existing 20 mL of 30% HCl solution. To find x, we will set up the equation 30%(20) + 100%(x) = 50%(20+x).

First, convert 30% to a decimal (0.3), and ounces to milliliters (1 ounce = 29.5735 mL).

Next, we solve the equation for x:
0.3(20) + 1(29.5735x) = 0.5(20 + 29.5735x). Solving for x gives us the volume in milliliters, which we then convert back to ounces.

After finding the value of x, we get the amount of pure acid needed to achieve the desired concentration.