Total no of black ppt which dissolves in yellow ammonium sulphide as well as hot and dil. Hno3Pbs, cus, hgs, cds, as2s3, as2s5, sb2s3, sb2s5, sns2, bi2s3

To determine which of the listed black precipitates dissolve in yellow ammonium sulfide and in hot, dilute nitric acid (HNO3), we need to analyze each compound's solubility characteristics. Let's break this down step by step.

Understanding the Compounds

The compounds you mentioned are:

• PbS (Lead(II) sulfide)
• CuS (Copper(II) sulfide)
• HgS (Mercury(II) sulfide)
• CdS (Cadmium sulfide)
• As2S3 (Arsenic trisulfide)
• As2S5 (Arsenic pentasulfide)
• Sb2S3 (Antimony trisulfide)
• Sb2S5 (Antimony pentasulfide)
• SnS2 (Tin(IV) sulfide)
• Bi2S3 (Bismuth sulfide)

Dissolution in Yellow Ammonium Sulfide

Yellow ammonium sulfide is known for its ability to dissolve certain metal sulfides. The following compounds from your list will dissolve in yellow ammonium sulfide:

• PbS
• CuS
• CdS
• Bi2S3

These sulfides form soluble complexes with the sulfide ions present in the ammonium sulfide solution.

Reactivity with Hot, Dilute Nitric Acid

Hot, dilute nitric acid can oxidize many sulfides, leading to their dissolution. The following compounds from your list will react with hot, dilute HNO3:

• PbS
• CuS
• HgS
• CdS
• As2S3
• Sb2S3

These sulfides typically convert to their respective metal nitrates or other soluble forms upon reaction with nitric acid.

Summary of Findings

In total, the black precipitates that dissolve in yellow ammonium sulfide are:

• PbS
• CuS
• CdS
• Bi2S3

And those that dissolve in hot, dilute HNO3 include:

• PbS
• CuS
• HgS
• CdS
• As2S3
• Sb2S3

Final Count

In summary, the total number of black precipitates that dissolve in yellow ammonium sulfide is four, while six dissolve in hot, dilute nitric acid. This analysis highlights the importance of understanding the chemical properties of these compounds to predict their behavior in different chemical environments.