The formula of the purple colour formed in Laissaigne’s test for sulphur using sodium nitroprusside is
- NaFe[Fe(CN)6]
- Na[Cr(NH3)2(NCS)4]
- Na2[Fe(CN)5(NO)]
- Na4[Fe(CN)5(NOS)]
The Correct Option is A
Solution and Explanation
The correct answer is (D) : Na4[Fe(CN)5(NOS)]
While preparation of Lassaigne's extract, sulphur from the organic compound reacts with sodium to form sodium sulphide.
\(Na + s → Na_2S \)
Sodium sulphide reacts with sodium nitroprusside to form violet colour compound, which confirms presence of Sulphur.
\(Na_2S + Na_2[Fe(CN)_5NO] → Na_4[Fe(CN)_5NOS]\)
Top Questions on sulphur
- Which of the following oxoacids of sulphur contains \(S\) in two different oxidation states?
- Which element has more electron gain enthalpy among chalcogen group?
- Match List - I with List - II
List I List II
A \(N _2( g )+3 H _2( g ) \rightarrow 2 NH _3( g )\) I \(Cu\)
B \(CO ( g )+3 H _2( g ) \rightarrow CH _4( g )+ H _2 O ( g )\) II \(Cu / ZnO - Cr _2 O _3\)
C \(CO ( g )+ H _2( g ) \rightarrow HCHO ( g )\) III \(Fe _x O _y+ K _2 O + Al _2 O _3\)
D \(CO ( g )+2 H _2\) (g) \(\rightarrow CH _3 OH ( g )\) IV \(Ni\)
Choose the correct answer from the optionsgiven below : - The oxoacid of sulphur that does not contain bond between sulphur atoms is :
- Identify the molecule which contains lone pair of electrons on the sulphur atom
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Concepts Used:
Sulphur
Sulfur, also spelled sulphur, is a nonmetallic chemical element with the atomic number 16 and symbol S. It is found in the earth's crust, oceans, and atmosphere in various forms such as sulfates, sulfides, and elemental sulfur. It is an essential element for all living organisms and is found in many important biomolecules like amino acids, vitamins, and coenzymes.
Sulfur has many industrial applications. It is used in the production of sulfuric acid, which is widely used in the chemical industry, as well as in the production of fertilizers, detergents, and other chemicals. Sulfur is also used in the vulcanization of rubber, as a component in gunpowder, and as a preservative in the wine-making process.
Sulfur is also known for its distinctive odor, which is often described as "rotten eggs." This odor is due to the presence of hydrogen sulfide, a compound that is formed when sulfur compounds break down in the presence of water.
Excessive exposure to sulfur compounds can be harmful to humans and animals. In high concentrations, sulfur dioxide, a common air pollutant, can cause respiratory problems. Hydrogen sulfide is also toxic in high concentrations and can be lethal in high doses.
In conclusion, sulfur is a versatile element with a variety of industrial and biological applications. While it is essential for life, it can also be harmful in high concentrations, so it is important to handle it with care.