Question

what is the ratio of water drops to EDTA if 2 drops of EDTA was needed to change the color of 20 drops of water with unknown hardness?

a. 10
b. 5
c. 0.1
d. 1.0

please explain..

Answer 1

Let's see. Bob Pursley did one early this AM that was 3 drops to 20 drops, so 3:20 (6.7) was the answer. Wouldn't this be done the same way?

Answer 2

so would the answer be a. 10??

Answer 3

That looks right to me.
H2O/EDTA = 20/3 = 6.7

H2O/EDTA = 20/2 = 10