Chemistry Q69 – JEE-MAIN 2026

Home Chemistry Basic ChemistryQuestion #41

Among

F e^{2 +}

P b^{2 +}

C u^{2 +}

and

M n^{2 +}

, identify the one that gets precipitated out while passing

H_{2} S

in presence of

N H_{4} O H

as group reagent. The highest possible oxidation state of the corresponding metal is

Clue 1 of 3: Qualitative Analysis Groups

Recall the classification of cations into groups based on their precipitation behavior with specific reagents.

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Step 1: Identify the Group Reagent and Precipitating Ions✦ Active

The group reagent $H_{2} S$ in the presence of $N H_{4} O H$ (ammonium sulfide) is used for the precipitation of Group IV (or Group III in some classifications) cations as their sulfides in an alkaline medium. Among the given ions:

- $P b^{2 +}$ and $C u^{2 +}$ belong to Group II, which precipitate as sulfides in acidic medium ( $H_{2} S$ in dilute $H C l$ ). While they would also precipitate in alkaline medium, they are not characteristic of this group reagent.

- Both $F e^{2 +}$ and $M n^{2 +}$ belong to Group IV (or Group III in some schemes) and precipitate as sulfides ( $F e S$ and $M n S$ ) in alkaline medium.

Step 2: Select the Most Characteristic Ion○ Expand

While both $F e^{2 +}$ and $M n^{2 +}$ precipitate under these conditions ( $F e S$ is black, $M n S$ is flesh-colored), $M n^{2 +}$ is a classic and unambiguous example of a Group IV cation that forms a distinct sulfide precipitate with $H_{2} S / N H_{4} O H$ . The question asks for 'the one', implying a single best fit.

💡 Teacher's Secret Hint

In multiple-choice questions with similar options, look for the most definitive or characteristic example.

Step 3: Determine the Highest Oxidation State of Manganese○ Expand

For Manganese ( $M n$ ), the highest possible oxidation state is $+ 7$ , which is observed in compounds like potassium permanganate ( $K M n O_{4}$ ). This corresponds to option 4.

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Chemistry Question 69 – JEE-MAIN 2026

Clue 1 of 3: Qualitative Analysis Groups

🧠 Full Solution Path