The volumes of two HCl solutions A (0.5N) and B(0.1N) to be mixed for preparing 2 L of 0.2 NHCl are:

Options

A. 0.5 L of `A^(+) 1.5L` of B
B. 1.5L of `A+0.5L` of B
C. 1L of `A+1L` of B
D. 0.75L of `A+1.25L` of B

Answer

A

Explanation

Let x L of A and (2-x) L of B are mixed
`((N_(1)V_(1) + N_(2)V_(2))/(V_(1) +V_(2)))= N_(3)`
`0.5 xx x+ 0.1 (2-x) = 0.2 xx 2 rArr (0.5-0.1) x= 0.4- 0.2`
`0.4 x= 0.2 rArr x= 0.5 rArr therefore 0.5` L of A and 1.5L of B should be mixed.