40 ml of 0.1 Mammonia is mixed with 20 ml of 0.1 M HCl. What is the pH of the mixture ? ( pK_(b) of ammoniasolution is 4.74)

40 ml of 0.1 Mammonia is mixed with 20 ml of 0.1 M HCl. What is the pH

1.	40 ml of 0.1 Mammonia is mixed with 20 ml of 0.1 M HCl. What is the pH of the mixture ? ( pK_(b) of ammoniasolution is 4.74)
Answer» 4.74 2.26 9.26 `5.00` Solution :40 ml of 0.1 M `NH_(3)` solution `= 40xx0.1` millimole = 4 millimoles `NH_(4)OH+HCl rarr NH_(4)CL + H_(2)O` 2 millimole of HCl will NEUTRALIZE 2 millimoles of `NH_(4)OH` to form 2 millimoles of `NH_(4)Cl`. `NH_(4)OH` left = 60 ml `:. [NH_(4)OH]=(2)/(60)M, [NH_(4)Cl]=(2)/(60)M` `pOH=pK_(b)+LOG .([NH_(4)Cl])/([NH_(4)OH])` `=4.74 + log .(2//60)/(2//60)=4.74` `:. pH=14-4.4.74=9.26`