50.0 ml of 0.100mol/L silver nitrate solution is titrated by 0.0900mol/L ammonium thiocyanate solution. Calculate : pSCN and pAg after addition of 50.0 ml of titrant.

To calculate the pSCN and pAg after the addition of 50.0 ml of titrant, we need to follow these steps:<br /><br />1. Calculate the moles of silver nitrate (AgNO3) in the 50.0 ml solution.<br />2. Calculate the moles of ammonium thiocyanate (NH4SCN) in the 50.0 ml solution.<br />3. Determine the reaction between AgNO3 and NH4SCN.<br />4. Calculate the remaining moles of AgNO3 and NH4SCN after the reaction.<br />5. Calculate the concentrations of Ag+ and SCN- in the final solution.<br />6. Calculate the pAg and pSCN values.<br /><br />Let's go through these steps:<br /><br />1. Moles of AgNO3:<br /> Moles of AgNO3 = Volume (L) x Concentration (mol/L)<br /> Moles of AgNO3 = 0.050 L x 0.100 mol/L = 0.005 mol<br /><br />2. Moles of NH4SCN:<br /> Moles of NH4SCN = Volume (L) x Concentration (mol/L)<br /> Moles of NH4SCN = 0.050 L x 0.0900 mol/L = 0.0045 mol<br /><br />3. Reaction between AgNO3 and NH4SCN:<br /> AgNO3 + NH4SCN → AgSCN + NH4NO3<br /> The reaction is a 1:1 stoichiometric reaction.<br /><br />4. Remaining moles after the reaction:<br /> Since the reaction is 1:1, the limiting reagent is NH4SCN.<br /> Remaining moles of AgNO3 = 0.005 mol - 0.0045 mol = 0.0005 mol<br /> Remaining moles of NH4SCN = 0 mol<br /><br />5. Concentrations in the final solution:<br /> Total volume after mixing = 50.0 ml + 50.0 ml = 100.0 ml = 0.100 L<br /> [Ag+] = Remaining moles / Total volume = 0.0005 mol / 0.100 L = 0.005 mol/L<br /> [SCN-] = 0 mol/L (since all NH4SCN has reacted)<br /><br />6. pAg and pSCN values:<br /> pAg = -log[Ag+] = -log(0.005) ≈ 2.30<br /> pSCN = -log[SCN-] = -log(0) = undefined (since [SCN-] is 0)<br /><br />Therefore, the pAg value is approximately 2.30, and the pSCN value is undefined.