Question

Hi, can this problem be worked out in detail please! Thank You.

Answer b was wrong

1. Starting with a stock solution containing 60 mg/dL of glucose, and using dH₂O as your diluting solution, you need to make 3 mL of each of the following glucose solutions: 60 mg/dL, 30 mg/dL, 15 mg/dL, 7.5 mg/dL, 3.75 mg/dL, and 1.875 mg/dL..

What is the volume of arrow E?

	a.	V1 x 2
	b.	V1 x df
	c.	V1 + V2
	d.	V1

Answer 1

To calculate the concentration of the solution with respect to the stock we will use the formula V1*S1 = V2*S2, where V1 = Volume of stock; S1= strength of stock; V2 = Volume of solution; S2 = strength of the solution.

Calculation for 30mg/dL solution having volume 3ml:

V1S1= V2S2

or V1*60 = 3*30

or V1 = 3/2

Similarly for calculating all the rest, V1 for 15mg/dl is 3/4; V1 for 7.5 mg/dl is 3/8; V1 for 3.75 mg/dl is 3/16; V1 for 1.875 mg/dl is 3/32. So it is evident that the volume V1 is reducing by a factor of 1/2 for each subsequent dilution step.

So Net volume V is option a: V1 * 2.