wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

The following reaction happens in which test ?
Na2S + Na2[Fe(CN)5NO] Na4[Fe(CN)5NOS]

A
Sodium sulphide test
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
Sodium nitroprusside test
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
Both A and B
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
None of the above
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B Sodium nitroprusside test

Lassaigne’s Test:

A small piece of a sodium metal is heated gently in a fusion tube till it melts to a shining globule. At this stage, a small amount of substance is added and the tube is heated strongly. The red hot tube is plunged into distilled water contained in a china dish. The contents are boiled for some time, cooled and then filtered. The filtrate is known as sodium extract or Lassaigne ‘s extract.

The extract contains sodium sulphide formed by the reaction between sulphur (present in the compound) and sodium:

2Na+SNa2S

The Lassaigne’s extract is divided into two parts and following tests are performed:

Lead acetate test: One part of the extract is acidified with acetic acid and then lead acetate solution is added. Formation of a black precipitate confirms the presence of sulphur in the organic compound.

Na2S+Pb(CH3COO)2PbS+2CH3COONa

Sodium nitroprusside test. A few drops of sodium nitroprusside solution are added to another part of the Lassaigne’s extract. The appearance of purple colouration confirms the presence of sulphur:

Na2S+Na2[Fe(CN)5NO]Na4[Fe(CN)5NO.S]


flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Oxides and Percentage of O
CHEMISTRY
Watch in App
Join BYJU'S Learning Program
CrossIcon