A buffer solution of pH 8.3 is prepared from ammonium chloride and ammonium hydroxide. Dissociation constant of ammonium hydroxide is `1.8xx10^(-5)`. What is the mole proportion of ammonium chloride and ammonium hydroxide?

Explanation

pOH = 14 - pH = 14 - 8.3 = 5.7
`pH=pK_(a)+"log"(["Salt"])/(["Base"])rArrpH=-log_(10)K_(a)+"log"(["Salt"])/(["Base"])`
`5.7=-log_(10)(1.8xx10^(-5))+"log"([NH_(4)Cl])/([NH_(4)OH])rArr5.7=5-log1.8+"log"([NH_(4)Cl])/([NH_(4)OH])`
`5.7=5-0.2553+"log"([NH_(4)Cl])/([NH_(4)OH])rArr5.7=4.7447+"log"([NH_(4)Cl])/([NH_(4)OH])`
`therefore([NH_(4)Cl])/([NH_(4)OH])=5.7-4.7447=0.9553`
`rArr([NH_(4)Cl])/([NH_(4)OH])="anti"log(0.9553)=9.022" "` The ratio is 9 : 1.