Question

0.5 m, 20 ml h3po4 solution is diluted to obtain 0.1n h3po4 solution. The volume of water required for this dilution is

Answer 1

Answer: 280 ml

Explanation:

M1 V1 = M2 V2

0.5 * 20 = (0.1/3) * V2

V2 = (0.5 * 20 * 3) / 0.1 = 300 ml

Vol. of H20 required = 300 - 20 = 280 ml

Answer 2

Answer: The volume of water required for dilution is 283.03 mL

Explanation:

The relation between normality and molarity follows:

$N=nM$

where,

N = normality of $H_3PO_4$ solution = 0.1

n = n-factor of $H_3PO_4$ solution = 3

M = molarity of $H_3PO_4$ solution = ?

Putting values in above equation, we get:

$0.1=3\times M\\\\M=\frac{0.1}{3}=0.033M$

To calculate the volume of the diluted solution, we use the equation:

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the molarity and volume of the concentrated phosphoric acid solution

$M_2\text{ and }V_2$ are the molarity and volume of diluted phosphoric acid solution

We are given:

$M_1=0.5M\\V_1=20mL\\M_2=0.033M\\V_2=?mL$

Putting values in above equation, we get:

$0.5\times 20=0.033\times V_2\\\\V_2=\frac{0.5\times 20}{0.033}=303.03mL$

To calculate the volume of water required, we subtract the total volume by the volume of concentrated solution.

$\text{Volume of water needed}=\text{Volume of diluted solution-Volume of concentrated solution}$

Volume of water needed = (303.03 - 20) mL = 283.03 mL

Hence, the volume of water required for dilution is 283.03 mL