To 5.85 gm of NaCl one kg of water is added to prepare a solution. What is the strength of NaCl in this solution (mol. wt. Of NaCl = 58.5)

Options

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

Answer

A

Explanation

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