Question

Show calculations AND explain how to prepare 275 mL of 1.0 M NaCl from solid sodium chloride. and Show calculations AND explain how to prepare 275 mL of 1.0 M NaCl from a 5.0 M stock solution of sodium chloride

Answer 1

Ans 1) Here volume of the solution = 275 ml=0.275L

Molar mass of NaCl= 23+35.5 =58.5 g/mol

Concentration of the solution = 1M

now,in order to make 275 ml of 1M NaCl from solid NaCl,

we would dissolve = volume x concenration x molar mass

                           = 0.275 x 1x 58.5

   = 16.08 g NaCl

i.e. 16.08 g NaCl is dissolved and the resulting solution is diluted to a final volume of 275 ml

ans 2) here Given, Volume of diluted solution V_d = 275ml=0.275L

Molarity of diluted solution M_d = 1M

Molarity of concentrated solution M_c = 5M

Let V_c be the volume of the concentrated solution

We Know V_cM_c=V_dM_d

V_c=V_dM_d / M_c

    = 0.275 x 1 /5

     =0.055L

      =55ml

Thus to prepare the desired solution we will take 55 ml of 5M stock solution and we will add enough water to make 275ml total volume of the solution.