Question

A 1100 ml. buffer solution is 0.110 mol L-in NH, and 0.125 mol Lin NH Br. Review Constants Periodic Table What mass of HCI will the buffer neutralize before the pH falls below 9.007(K,(NH) - 1.76 x 10-5 Express your answer using two significant figures AERO me Submit Previous Answers Request Answer X Incorrect; Try Again Part B N H, and 0.390 mol L'in NH Br, what mass of HCl could If the same volume of the buffer were 0.265 mol L be handled before the pit fell below 9.00? Express your answer using two significant figures

Answer 1

The Buffer solution NHABrs solution. Contains o.110M Nity and 0.125m polt - [ NH Br] Pro + log [ Nito) 0.125 - - log 176x10 +logo. 110 = 4,81 pH = 14-POH = 14.00-9.89 = 9.19 When He added to the Buffer solution then following reaction will occur- Nit & Htci - NHA + i So with addition of Hel amount of Nitz decreases and Futa Increases. Initially 110mL Buffer Contains 0.110 mx 110 ml 0.0121 mol Nha 10oome 0.125 mol x llon 20101373 mol Nita 1000 m

the ph Now, Let x mat He has to be added to reduce below 9.00 . After addition of a mot Ha, Amount of NH3 - (0.0121 - x) mol Amount of titaa (0,01375 +2) mol amount of Nitat amount of NH3 pot - 14-4 - 14-9.0 - 50 I . 6.0 = 4.75 + log 0.01375 ta 5.0 = 4.75 + log 010121 & 2 0,01375 x - 20.25 0.0121 in 0.01345 + 10B 0.6121 -x 1.78 0,01375 + x = 0.0215 - 178 x 2.78 n = 0.00775 0.00775 = 0.00278 moles. n = 2.78 : Mass of He to be added 20.00278 mo g. x 36.5 / gnoj = 0.10175 g 101.75 mg.