The base imidazole has Kb of 1.0×10−7. What volumes of 0.02 M HCl and 0.02 M imidazole should be mixed to make 150 mL of a buffer of pH 7 ?
50 mL and 100 mL
Let x ml of the acid be used. Volume of base mixed = 150 - xml
Volume of base left = 150 - x - x = 150 - 2x
pOH = 14 - pH = 14 - 7 = 7
=pKb+log[Salt][Base]=−log 1.0×10−7+logx150−2x;logx150−2x=0=log 1or,x150−2x=1⇒x=50ml