`{:(NH_(4)OHhArr, NH_(4)^(+)+,OH^(-)), (1,0,0),(C(1-alpha),Calpha,Calpha):}`
given , `pH=11`
`:. [H^(+)]=10^(-11)` , `[.:[H^(+)][OH^(-)]=10^(-14)]`
`:. [OH^(-)]=10^(-3)=Calpha` , `("Since", C=0.05)`
`:. alpha=(10^(-3))/(C )= (10^(-3))/(0.05)=2xx10^(-2)`
`=0.02` or `2%`