Find the number of ions which are soluble in excess of NaOH as well as excess of $NH_{4} OH$
$A g^{+}, P b^{+ 2}, A l^{+ 3}, S n^{+ 2}, Z n^{+ 2}, C d^{+ 2}$

Question

Find the number of ions which are soluble in excess of NaOH as well as excess of NH 4 ​ OH A g + , P b + 2 , A l + 3 , S n + 2 , Z n + 2 , C d + 2

TestHub · Accepted Answer

The ions that are soluble in excess NaOH and excess NH₄OH are amphoteric.

Ag⁺ forms [Ag(NH₃)₂]⁺ with NH₄OH but precipitates as Ag₂O with NaOH.

Pb²⁺, Al³⁺, Sn²⁺, Zn²⁺ are soluble in excess NaOH (forming hydroxo complexes) but only Zn²⁺ is soluble in excess NH₄OH (forming [Zn(NH₃)₄]²⁺).

Cd²⁺ is not soluble in excess NH₄OH or NaOH.

Therefore, only Zn²⁺ satisfies both conditions.

The final answer is $1$

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