Answer :
Here, M = number of moles/volume of solution (L)
1 L = 1000 mL ===> 727.6 mL = 0.7276 L
3.77 M = 3.77 mol/L (concentration of the solution
Solute = MgCl2
M = No. of moles/volume
M x volume = No of moles MgCl2
3.77 mol/L x 0.7276 L = No of moles MgCl2
2.76 moles = No of moles MgCl2
Answer: 2.76 moles