Question

PLEASE HELP!

10 ml bromocresol green is placed in a 50ml volumetric flask and diluted to the mark with 0.4M HCl. What is this new concentration?

The other given information is
a) BG contains 80mg/L
b) molar mass of BG is 698g/mol

Any help is much appreciated :)

Answer 1

How many mL of 0.4M HCl do you have?

Answer 2

I assume its 40ml HCl since i placed 10ml of bromocresol green and diluted it up to the 50ml mark

Answer 3

1st of all find the molarity of BG, i.e moles/L
Molarity=80X10^-3 / 698 = 1.14 X 10^-4 mole/L
now for dilution Use the formula:
C1V1 = C2V2
1.14 X 10^-4 X 10 = C2 X 50
C2 = 1.14X10^-4 X 10 / 50 = 2.29 X 10^-5 moles / L is the answer