Find the compound \( A \) from the following reaction sequences:
\[
A \xrightarrow{\text{aqua regia}} B \xrightarrow{(1) \, \text{KNO}_3, \, \text{NH}_4\text{OH}} \text{yellow ppt}.
\]
Show Hint
- \( \text{CoS} \)
- \( \text{NiS} \)
- \( \text{ZnS} \)
- \( \text{MnS} \)
The Correct Option is B
Solution and Explanation
- The subsequent treatment with \( \text{KNO}_3 \) and \( \text{NH}_4\text{OH} \) forms a precipitate.
- The yellow precipitate suggests the formation of \( \text{NiS} \) (nickel sulfide), which forms when nickel ions react with sulfide ions.
Thus, the compound \( A \) must be \( \text{Ni} \), which reacts with aqua regia to form \( \text{Ni}^{2+} \), and then precipitates as \( \text{NiS} \).
Final Answer: \( \text{NiS} \).
Top Questions on Organic Chemistry
Given below are two statements:
Statement I: Experimentally determined oxygen-oxygen bond lengths in the \( O_2 \) are found to be the same and the bond length is greater than that of a \( O=O \) (double bond) but less than that of a single \( O-O \) bond.
Statement II: The strong lone pair-lone pair repulsion between oxygen atoms is solely responsible for the fact that the bond length in ozone is smaller than that of a double bond \( O=O \) but more than that of a single bond \( O-O \).
In light of the above statements, choose the correct answer from the options given below:- JEE Main - 2025
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Identify correct statement/s:
(A) \( -\text{OCH}_3 \) and \( -\text{NHCOCH}_3 \) are activating groups.
(B) \( -\text{CN} \) and \( -\text{OH} \) are meta directing groups.
(C) \( -\text{CN} \) and \( -\text{SO}_3\text{H} \) are meta directing groups.
(D) Activating groups act as ortho- and para-directing groups.
(E) Halides are activating groups.
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- Match List - I with List - II.
\[ \begin{array}{|c|c|} \hline \text{List - I} & \text{List - II} \\ \hline \text{(A) } \text{Ti}^{3+} & \text{(I) } 3.87 \\ \text{(B) } \text{V}^{2+} & \text{(II) } 0.00 \\ \text{(C) } \text{Ni}^{2+} & \text{(III) } 1.73 \\ \text{(D) } \text{Sc}^{3+} & \text{(IV) } 2.84 \\ \hline \end{array} \]
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Match List - I with List - II:
Choose the correct answer from the options given below:
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Match List - I with List - II:
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