Hello, Please help me! Thank you 1. Give the formula for a chemical substance wh

Question

Hello,

Please help me!

Thank you

1. Give the formula for a chemical substance which will yield a precipitate (if excess of (15 pts) substance is required, so state): A. with Cr3 solution but not with Mn2+ solution. B. with both Fe3+ solution and Co2 solution. C. with NiCl2 solution but not with CrCl3 solution. D. with Mn(NO3)2 solution but not with KNO3 solution. E. with Al(NO3)3 solution but not with Zn(NO3)2 solution. 2. Give the formula for a solid hydroxide [e.g. Ni(OH2l of the aluminum-nickel group cations (15 pts) which will: A. Dissolve readily in 15 M NH3 and also in 8 M NaOH B. Dissolve in 8 M NaOH but not in 15 M NH3. C. Dissolve in 15 M NH3 but not in 8 M NaOH. 51

Explanation / Answer

1. All these cations belong to Group(|||) cation,these are:-
cobalt(II) Co2+, Nickel(II) Ni2+, iron(II) Fe2+, iron(III) Fe3+, chromium(III) Cr3+, aluminium(III) Al3+, zinc(II) Zn2+, manganese(II) Mn2+, manganese(VII) Mn7+. for this we need to know the quantitative analysis.
A.) NH3 + NH4Cl (In this solution Cr3+ will ppt. as hydroxide but Mn2+ will not.)
Cr3+ + 3NH3 + 3H2O ? Cr(OH)3? + 3NH4+

B.) (NH4)2S + NH3 + NH4Cl
C.)  NaOH and NaOCl solutions ( Ni2+ precipitate outs as hydroxide salts, while Cr3+ remain in solution)
D.) NH3 + NH4Cl

E.)  NH3 + NH4Cl

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