Answer :
The volume of KCN = 0.356 L
Further explanation
Molarity is a way to express the concentration of the solution
Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution
[tex]\large{\boxed {\bold {M ~ = ~ \frac {n} {V}}}[/tex]
Where
M = Molarity
n = number of moles of solute
V = Volume of solution
mol of KCN = 7.47 x 10⁻³
Molarity of KCN = 0.0210 M
The volume :
V = n : M
V = 7.47 x 10⁻³ : 0.0210
V = 0.356 L