To a concentrated buffer of pH 4.0 is added an equal volume of an aqueous solution that is 0.020 M in Cr3+, Cd2+ and Al3+. The expected precipitate would consist of ________.
salt chromium(III) hydroxide cadmium hydroxide aluminum hydroxide
Ksp 6.3 × 10-31 2.5 × 10-14 1.3 × 10-33
◦ Al(OH)3
◦ Al(OH)3 and Cr(OH)3
◦ Cd(OH)2
◦ Cd(OH)2 and Cr(OH)3
◦ Cd(OH)2, Cr(OH)3 and Al(OH)3