InterviewSolution
Saved Bookmarks
| 1. |
In what volume ratio should you mix `1.00 M` solution `NH_(4)Cl` and 1.00 M `NH_(3)` to produce a buffer solution of pH 9.80 ? `[pK_(b)(NH_(3))=4.74]`A. `1:1.35`B. `3.5 :1`C. `2:1`D. `1:2` |
|
Answer» Correct Answer - B `[NH_(4)Cl]=V_(1)mL =V_(1)` millimol `[NH_(3)]=V_(2)mL =V_(2)` millimol `=pH =9.80 , pOH =4.2` `pOH =pK_(a)+log.(V_(1))/(V_(2))` `4.2 =4.74 +log. (V_(1))/(V_(2))` `-0.54=log. (V_(1))/(V_(2))` or `log.(V_(2))/(V_(1))=0.54` `(V_(2))/(V_(1))=` antilog `0.54=3.5` Thusl, `(V_(2))/(V_(1))=(3.5 )/(1)` |
|