Please tell me the solution of Q 2004 and Q 2005 Q2004 Sodium hydroxide solution is added first - Chemistry - Analytical Chemistry Uses of Ammonium Hydroxide and Sodium Hydroxide

Question

Please tell me the solution of Q 2004 and Q 2005
Q2004 Sodium hydroxide solution is added first in
a small amount, then in excess to the aqueous salt solutions of
a] copper [II] sulphate b] zinc nitrate c] lead nitrate d] iron
[III] sulphate State in each case-
i] the colour of the precipitate when NaOH is added in a small
quantity;
ii) the nature of precipitate [i e soluble or insoluble ] when NaOH
is added in excess
Write balanced equations for - a] Aluminium b] Zinc - is warmed
with NaOH [ caustic soda ] soln

Q2005 The questions below refers to the following
salt solutions listed A to F: A :- Copper nitrate
B: Iron [II] sulphate, C : Iron [III] chloride, D : Lead nitrate, E
: Magnesium sulphate, F : Zinc chloride
i] Which soln becomes a deep / inky blue colour when excess of
ammonium hydroxide is added to it
ii] Which solution gives a white precipitate with excess ammonium
hydroxide solution

Akansha Chauhan · Accepted Answer

Dear Student,

2005

Solution

a) Copper nitrate

When alkali metals are dissolved in liquid ammonia, the alkali
metal atom readily loses the valence electron Both the cation and
the electron combine with ammonia to form ammoniated cation and
ammoniated electron

M + (x+y)NH3 → [M(NH3)x]+ + [e(NH3)y]-

The ammoniated electron is responsible for the blue colour of the
solution

b) Magnesium sulphate
MgSO4 + NH4OH --> Mg(OH)2 +
(NH4)2 SO4

White colour = Magnesium sulphate
Kindly post remaining query in next thread
Regards