The pOH at which 0.01 M Co 2+ ions in solution precipitate down as Co ( OH )2 is . ( K sp . of Co ( OH )2 is .2.5 × 10-16)

Question

The pOH at which 0.01 M Co 2+ ions in solution precipitate down as Co ( OH )2 is . ( K sp . of Co ( OH )2 is .2.5 × 10-16) (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

Co ( OH )2( s ) leftharpoons Co 2+( aq )+2 OH ( aq ) [ Co 2+][ bar O H ]2= K sp =2.5 × 10-16 (0.01)[ bar O H ]2=2.5 × 10-16 [ bar O H ]2=(2.5 × 10-16/0.01)=2.5 × 10-14 [ bar O H ]=√2.5 × 10-14 =1.58 × 10-7 M pOH = -log 1.58 × 10-7 = 6.8

Q. The pOH at which 0.01MCo2+ ions in solution precipitate down as Co(OH)2​ is _______. (Ksp​ of Co(OH)2​ is 2.5×10−16)

Co(OH)2​(s)⇌Co2+(aq)+2OH(aq) [Co2+][OˉH]2=Ksp​=2.5×10−16 (0.01)[OˉH]2=2.5×10−16 [OˉH]2=0.012.5×10−16​=2.5×10−14 [OˉH]=2.5×10−14​ =1.58×10−7M pOH=−log1.58×10−7=6.8

Q. The $pO H$ at which $0.01 M C o^{2 +}$ ions in solution precipitate down as $C o (O H)_{2}$ is _______.
$(K_{s p}$ of $C o (O H)_{2}$ is $2.5 \times 1 0^{- 16})$