Question

what is the [H3O+] and pH of the solution that results when 35 mL of 0.020 M HNO3 is mixed with 35 mL of 0.020 M NH3?

Answer 1

The complete step wise calculation is given as below:-

It is given that, volume af HNO3 = 35mL = 358103 LI since, Im L= 103 L Concentrationaf HNO3 = 0.020 M = 0.020 mol/l Number of moles of nro 3 = 35x16-3 x0.02 moles = 0.7 X10-3 moles moles of HNO2 = 0.7 mmol es (since, to 3 moles Elmmole)

Concentration af NH3= 0.02m=0.02 mol/L volume of NH3 = 35 mL Number of moles af NH3 = 3580.02 mmoles = 0.7 mmoles - ② since, this is a neutralization reaction of acid (HNO3) and base (NH3). So, the remainining number of moles -0.7 -0.7) 20 mmoles. This can happens only at neutral pH=7. Then pH=7 and [F3 of] = 10x1077 PH = -log [307]