A metal nitrate reacts with KI to give a black precipitate which on addition of excess of KI is converted into orange colour solution. The cation of the metal nitrate is (2005S)(a) Hg²⁺ (b) Bi³⁺ (c) Pb²⁺ (d)Cu⁺
Answers
Answer:
(b) Bi³⁺ is the correct answer.
Explanation:
A metal nitrate reacts with KI to give a black precipitate which on addition of excess of KI is converted into orange colour solution.
To find:
The cation of the metal nitrate =?
Bismuth nitrate will react with KI to give bismuth iodide.
The reaction goes as follows
Bi(NO3)3 + KI ===> BiI3 + 3KNO3
Thus BiI3 is a black precipiate formed in the reaction.
When BiI3 is reacted with excess amount of KI, K[BiI4] will be formed.
The reaction is as follows:
BiI3 + KI ==> K[BiI4]
The precipate formed is orange in colour.
Thus (b) Bi³⁺ is the correct answer.
KI is potassium iodide.
It is a colourless crystalline solid.
BiI3 is bismuth iodide.
It is a grayish black solid.
Bi(NO3)3 is bismuth nitrate.
It is a solid white in colour.