Ksp of Al(OH)3 is 1.0×10−15. pH of the saturated solution is about

Al(OH)3⇌Al3++3OH−                      S           3S∴ Ksp=Al3+OH−3⇒1×10−15=27S4 S=1×10−152714=7.8×10−5 ∴ OH−=3S=2.34×10−4 ∴ pOH=−logOH−=3.63 ∴ pH=10.37≈10.4