Question

How many mL of 17 M NH3 must be diluted to 500.0 mL to make a 0.75 M solution?

(a) 13 mL
(b) 22 mL
(c) 39 mL
(d) 73 mL
(e) None of these

Answer 1

Answer: To solve this problem, we can use the concept of the dilution formula:

C1V1 = C2V2

Where:

C1 = initial concentration of the concentrated solution (in M)

V1 = volume of the concentrated solution to be taken (in mL)

C2 = final concentration of the diluted solution (in M)

V2 = final volume of the diluted solution (in mL)

Given:

C1 = 17 M (concentration of the concentrated NH3 solution)

V2 = 500.0 mL (final volume of the diluted solution)

C2 = 0.75 M (final concentration of the diluted NH3 solution)

We need to find V1 (volume of the concentrated NH3 solution to be taken).

Now, let's plug the values into the dilution formula:

17 M x V1 = 0.75 M x 500.0 mL

Solving for V1:

V1 = (0.75 M x 500.0 mL) / 17 M

V1 ≈ 22.06 mL

Rounded to the nearest whole number, V1 is approximately 22 mL.

So, the correct answer is (b) 22 mL.