6. 8.50 ml of a standardized 0.05120mol/L silver nitrate solution was used to titrate 10.00 ml of ammonium thiocyanate solution . Calculate the molar concentration of ammonium thiocyanate solution

To calculate the molar concentration of the ammonium thiocyanate solution, we can use the concept of stoichiometry and the fact that the reaction between silver nitrate (AgNO₃) and ammonium thiocyanate (NH₄SCN) is a 1:1 molar ratio.<br /><br />The balanced chemical equation for the reaction is:<br />\[ \text{AgNO}_3 + \text{NH}_4\text{SCN} \rightarrow \text{AgSCN} + \text{NH}_4\text{NO}_3 \]<br /><br />Given:<br />- Volume of silver nitrate solution used: 8.50 mL<br />- Molarity of silver nitrate solution: 0.05120 mol/L<br />- Volume of ammonium thiocyanate solution: 10.00 mL<br /><br />First, calculate the number of moles of silver nitrate used in the titration:<br />\[ \text{Moles of AgNO}_3 = \text{Molarity} \times \text{Volume (in liters)} \]<br />\[ \text{Moles of AgNO}_3 = 0.05120 \, \text{mol/L} \times \frac{8.50 \, \text{mL}}{1000 \, \text{mL/L}} \]<br />\[ \text{Moles of AgNO}_3 = 0.05120 \, \text{mol/L} \times 0.00850 \, \text{L} \]<br />\[ \text{Moles of AgNO}_3 = 0.0004356 \, \text{mol} \]<br /><br />Since the reaction is 1:1, the moles of NH₄SCN will be the same as the moles of AgNO₃:<br />\[ \text{Moles of NH}_4\text{SCN} = 0.0004356 \, \text{mol} \]<br /><br />Now, calculate the molar concentration of the ammonium thiocyanate solution:<br />\[ \text{Molarity of NH}_4\text{SCN} = \frac{\text{Moles of NH}_4\text{SCN}}{\text{Volume of NH}_4\text{SCN solution (in liters)}} \]<br />\[ \text{Molarity of NH}_4\text{SCN} = \frac{0.0004356 \, \text{mol}}{10.00 \, \text{mL} / 1000 \, \text{mL/L}} \]<br />\[ \text{Molarity of NH}_4\text{SCN} = \frac{0.0004356 \, \text{mol}}{0.010 \, \text{L}} \]<br />\[ \text{Molarity of NH}_4\text{SCN} = 0.04356 \, \text{mol/L} \]<br /><br />Therefore, the molar concentration of the ammonium thiocyanate solution is \( 0.04356 \, \text{mol/L} \).