4 L of 0.02 M aqueous solution of NaCl was diluted by adding one litre of water. The molality of the resultant solution is ……

Options

A. `0.004`
B. `0.008`
C. `0.012`
D. `0.016`

Answer

D

Explanation

Explanation :
Apply the reaction : `M_(1)V_(1)=M_(2)V_(2)`
Given : `M_(1)=0.02 M, V_(1)=4 L, M_(2)=? V_(2)=5L`
Therefore, `0.02xx4L=M_(2)xx 5L`
`M_(2)=0.08//5=0.016 M`