if the density of a 3 M aq solution of NaCl is 1.25 g/ml, what will be its molality?

Dear student,

3M solution means 1000mL solution contains 3 moles of NaCl.

Hence, 1000 mL×1.25 g/mL =1250 g solution contains 3 moles of NaCl.
Mass of solvent =1250-3×58.5=1074.5 g
1074.5 g solvent contains 3 moles NaCl

​Hence 1000g solvent will contain 31074.5×1000=2.79 moles

Hence molarity is 2.79 m

Hope this helps,


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