EX/Cupper(I)Iodide *What was happen if excess amount of potassium iodide and sodium thiosulfate added?

*How can increase rate of the reaction?

*What is role of the product washing by water, ethanol and ether?​

Explanation:

Copper sulphate reacts with potassium iodide to form cuprous iodide and iodine.

2CuSO

4

+4KI→Cu

2

I

2

↓+I

2

+2K

2

SO

4

Thus, CuI

2

is not formed in this reaction.

Hence, the option B is incorrect and option A is correct.

The liberated iodine is titrated with sodium thiosulphate to form sodium tetrathionate.

2Na

2

S

2

O

3

+I

2

→Na

2

S

4

O

6

+2NaI

Iodine is reduced and sodium thiosulphate is oxidized.