Question

What will be the resultant pH, when 200 mL of an aqueous solution of `HCI(pH=2.0)` is mixed with 300 mL of an aqueous solution of `NaOH(pH=12.0)` ?
A. `11.0310`
B. `11.3010`
C. `10.000`
D. None of these

Answer 1

Correct Answer - B
`pH of HCI =2` , `:. [HCI]=10^(-2)M`
`pH of NaOH = 12` , `:. [NaOH]= 10^(-2)M`
`{:(,HCI+,NaOHrarr,NaCI+,H_(2)O),("Meq. before reaction", 200xx10^(-2),300xx10^(-2), ,),(, =2,=3,0,0),("Meq. after reaction", 0,1,2,2):}`
`:. [OH^(-)]` left from `NaOH=(1)/(500)=2xx10^(-3)M`
`:. pOH= -log [OH^(-)]= -log 2x10^(-3)`
`:. pOH=2.6989 and pH = 11.3010`