The formula for molarity is
#"molarity" = "mol solute"/"L soln"#
We therefore need to find the number of moles of #"HCl"# and the number of liters of solution.
The moles of #"HCl"# is found via its molar mass (#36.46# #"g/mol"#):
#44.78cancel("g HCl")((1color(white)(l)"mol HCl")/(36.46cancel("g HCl"))) = color(red)(1.228# #color(red)("mol HCl"#
The number of liters of solution is
#730.05cancel("mL")((1color(white)(l)"L")/(10^3cancel("mL"))) = color(green)(0.73005# #color(green)("L"#
Plugging these into the molarity equation, we have
#"molarity" = (color(red)(1.228)color(white)(l)color(red)("mol"))/(color(green)(0.73005)color(white)(l)color(green)("L")) = color(blue)(1.682M#
