Which of the following should be done in order to prepare 0.40 M NaCI starting with 100 ml of 0.30 M NaCI (Mol. Mass of NaCI = 58.5)?

Options

A. Add 0.585 g NaCl
B. Add 20 ml water
C. Add 0.010ml NaCl
D. Evaporate 10ml water

Answer

A

Explanation

100 ml. of `0.30 M =(100xx0.3)/(1000)=0.03` mole of NaCl
100 ml of `0.40 M =(100xx0.4)/(1000)=0.04` mole of NaCl
Moles of NaCl to be added = 0.04-0.03 =0.01 mole
= 0.585 gm