In the qualitative analysis scheme for metal ions, how are the analytical group iii cations separated from the cations of analytical groups iv and v? a. by addition of hcl, forming insoluble metal chlorides b. by addition of h2s in basic solution, forming insoluble metal sulfides or hydroxides c. by addition of h2s in acidic solution, forming insoluble metal sulfides d. by addition of (nh4)2co3 or (nh4)3po4, forming insoluble metal carbonates or phosphates e. by addition of h2so4, forming insoluble metal sulfates