Question

if Fe(NO3)3 is dissolved in enough water to make exactly 323 ml of solution, what is the molar concentartion of nitrate ion g

Answer 1

The given question is incomplete. the complete question is : If 5.15 g$Fe(NO_3)_3$ is dissolved in enough water to make exactly 323 ml of solution, what is the molar concentartion of nitrate ion.

Answer:  The molar concentartion of nitrate ion is 0.195.

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

Given : 5.15 g of $Fe(NO_3)_3$ is dissolved

Volume of solution = 323 ml

$Molarity=\frac{n\times 1000}{V_s}$

where,

n= moles of solute

$Moles=\frac{\text{Given mass}}{\text{Molar mass}}=\frac{5.15g}{242g/mol}=0.021moles$  

$V_s$ = volume of solution = 323 ml

$Molarity=\frac{0.021\times 1000}{323}=0.065M$

As 1 M of $Fe(NO_3)_3$ gives 3 M of $NO_3^-$ ions.

Thus 0.065 M of $Fe(NO_3)_3$ gives  = $\frac{3}{1}\times 0.065=0.195M$ of $NO_3^-$ ions.

The molar concentartion of nitrate ion is 0.195.