Q31. Molality ( m ) of 3 M aqueous solution of NaCl is : (Given : Density of solution $= 1.25 \mathrm {~g} \mathrm {~mL} ^ { - 1 }$, Molar mass in $\mathrm { gmol } ^ { - 1 } : \mathrm { Na } - 23 , \mathrm { Cl } - 35.5$ )\\
(1) 1.9 m\\
(2) 3.85 m\\
(3) 2.79 m\\
(4) 2.90 m