Two solutions of HCl, A and B have concentration of 0.5 N and 0.1 M respectively . The volume of solutions A and B required to make 2 L of 0.2 N HCl are

Options

A. 0.5 L of A + 1.5 L of B
B. 1.5 L of A + 0.5 L of B
C. 1.0 L of A + 1.0 L of B
D. 0.75 L of A + 1.25 L of B

Answer

A

Explanation

Let volume of A = x L
Volume of B = (2 - x)L
`because M_(1)V_(1)+M_(2)V_(2)=M(V_(1)+V_(2))`
`implies 0.5x+0.1(2-x)=0.2(x+2-x)`
(`because` for HCl, 0.1M HCl = 0.1N HCl)
`implies 0.5x+0.2-0.1x=0.2xx2`
`implies0.4x+0.2=0.4implies0.4x=0.2`
`therefore x=(0.2)/(0.4)=0.5L`
Since x = 0.5 L (vol. of A), then
`2-x=2-0.5=1.5L` (Vol. of B).