Question

What will be the required volumes of 1N HCl and 4N NaOH to prepare one litre solution of pH 7?

Answer 1

by law of gram equivalents vol. of hcl x normality=vol. of naoh x normality of naoh...
so Vx1=4xV'
so V'=V/4
total vol. is 1L= V+V/4 that is on solving
V =0.8L
and V'=0.2 L

Answer 2

Answer: The 0.8 L of 1 N HCl solution and 0.2 L of 4 N NaOH solution.

Explanation

Normality of the HCl solution,$N_1$ = 1N

Normality of NaOH solution,$N_2$ = 1N = 4 N

Total volume of solution to be prepared = 1 l

Let the volume of the HCl require be V liters and the volume of NaOH br (1-V) liters.

Volume of HCl required $V_1$ =V

Volume of NaOH required $V_2$ =1-V

To prepare one litre solution of pH 7

$N_1V_1=N_2V_2$

$1 N\times V=4N\times (1-V)$

$V=0.8 L$

Volume of HCl required = V= 0.8 L

Volume of NaOH required = 1 - V= 1L - 0.8 L = 0.2 L