250 ml of a sodium carbonate solution contains 2.65 grams of Na2CO3. If 10 ml of this solution is diluted to one litre, what is the concentration of the resultant solution (mol. wt. of Na2CO3 = 106)

Molarity=Wg ×  1000molecular  wt. ×  Vml.                =2.65  ×  1000106  ×  250=0.1  M10 ml  of  this  solution is  diluted  to 1000  ml  M1V1=M2V2.1  ×  10 =x  x 1000 x=0.1 ×  101000  =  0.001 M.