Question

Slaked lime, `Ca(OH)_(2)` is used extensively in sewage treatment. What is themaximum pH that can be estabilished in `Ca(OH)_(2)(aq)` ?
`Ca(OH)_(2(s))hArr Ca_((aq.))+2OH_((aq.))^(-), (K_(SP)=5.5xx10^(-6))`
A. `1.66`
B. `12.3471`
C. `7.0`
D. `14.0`

Answer 1

Correct Answer - B
`K_(SP)of Ca(OH)_(2)=4S^(3)=5.5xx10^(-6)`
`:. S= 3sqrt((5.5xx10^(-6))/(4))=1.11xx10^(-2)`
`:. [OH^(-)]=2S=2xx1.11xx10^(-2)`
`:. pOH=1.6528 :. pH =12.3471`