Answer: Molality of a saline solution = 1.14 moles per kg
Explanation:
Given mass of NaCl (m)= 50.0 g
Mass of solvent = 0.750 kg
Molar mass of NaCl (M)= 23 g + 35.5 g = 58.5g [Atomic mass of Na = 23 u , atomic mass of Cl = 35.5 u]
Number of moles (n) =[tex]\dfrac{m}{M}[/tex]
[tex]\dfrac{50}{58.5}=.8547[/tex]
Molality = [tex]\dfrac{\text{Number of moles }}{\text{Mass of solvent in kg}}[/tex]
[tex]=\dfrac{0.8547}{0.750}=1.1396\approx1.14\text{ moles per kg][/tex]
Hence, molality of a saline solution = 1.14 moles per kg
