Question

How many mL of anti-D reagent are needed to prepare 5 mL of a 1:25 dilution^

a 0.1
b 0.2
c 0.25
d 0.5

Answer 1

To prepare a 1:25 dilution in 5 mL, 0.2 mL of anti-D reagent is needed.

Step-by-step explanation:

To determine the amount of anti-D reagent needed to prepare a dilution, we can use the dilution formula:

(V1)(C1) = (V2)(C2)

Where:

V1 = volume of stock solution

C1 = concentration of stock solution

V2 = volume of diluted solution

C2 = concentration of diluted solution

In this case, we know that:

V1 = ? (unknown)

C1 = 1:25 dilution

V2 = 5 mL

C2 = concentration of diluted solution (unknown)

Since the dilution is expressed as a ratio, we can convert it to a decimal by taking the reciprocal (1/25 = 0.04).

Plugging these values into the dilution formula:

(V1)(0.04) = (5 mL)(C2)

Solving for V1:

V1 = (5 mL)(C2) / (0.04)

Since we're looking for the volume in mL, the answer is 0.2 mL (option b).

Answer 2

To prepare 5 mL of a 1:25 dilution, 0.2 mL of the anti-D reagent is required, The correct option is B.

Step-by-step explanation:

The question asks how many mL of anti-D reagent are needed to prepare 5 mL of a 1:25 dilution. A 1:25 dilution means that 1 part of the concentrated solution (the anti-D reagent) is mixed with 24 parts of the diluent for a total of 25 parts. Since the total volume needed is 5 mL, each part (one out of 25) represents 5mL divided by 25.

Calculating this, we get: 5 mL ÷ 25 = 0.2 mL. Thus, 0.2 mL of the anti-D reagent is necessary to prepare 5 mL of a 1:25 dilution. This aligns with option 'b' from the multiple-choice answers provided.

To prepare a 1:25 dilution, you need to determine the volume of anti-D reagent needed to dilute 5 mL of the solution. The dilution factor is the inverse of the ratio, so 1:25 is equivalent to 25:1. Using the dilution formula, C1V1 = C2V2, where C1 is the initial concentration, V1 is the initial volume, C2 is the final concentration, and V2 is the final volume, we can calculate the volume of anti-D reagent needed:

C1V1 = C2V2

V1 = (C2V2)/C1

V1 = (25)(5 mL)/(1) = 125 mL

Therefore, you would need 125 mL of anti-D reagent to prepare 5 mL of a 1:25 dilution. The correct option is B.