Question

n today's experiment, Solutions A and B are prepared as follows. Solution A: Solution B: 2.0 mL of 3.00 x 10-4 M bromcresol green 2.0 mL of 3.00 x 10-4 M bromcresol green 5.0 mL of 1.60 M acetic acid (HAc) 2.0 mL of 0.160 M sodium acetate (NaAc) 2.0 mL of 0.200 M KCl diluted to a total volume of 50 mL diluted to a total volume of 50 mL How many mL of Solution A must be added to Solution B to give a buffer that is equimolar in HAc and Ac-

Answer 1

Answer:

2 mL of Solution A must be added to Solution B to give a buffer that is equimolar.

Explanation:

 Given the data in the question;

First we determine the number of sodium acetate;  

⇒ molarity × volume ( L )

⇒ 0.16 × 2.0 mL

⇒ 0.16 × 0.002 L

⇒ 0.00032

Now, Molarity of sodium acetate = moles / Volume(L)

⇒ ( 0.00032 / 50 ) × 1000

⇒ 0.0064

Since number of moles of acetic acid that should be added tp make equimolar solution is 0.00032

and Molarity of acetic acid is 0.16 molL⁻¹

Let X represent the volume that should be added.

so;

Molarity = Moles / Volume (L)

we substitute

0.16 = (0.00032  / X) × 1000

0.16 = 32 / X

X = 0.32 / 0.16

X = 2 mL

Therefore, 2 mL of Solution A must be added to Solution B to give a buffer that is equimolar.