Multiple choice

After reaction with potassium iodide and copper sulphate, sodium thiosulphate solution is added. Find the incorrect statement about this reaction.

  1. Cu2I2 is formed.

  2. CuI2 is formed.

  3. Na2S2O3 is oxidised.

  4. Evolved I2 is reduced.

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When KI is added to the solution of cupper sulphate, an equivalent amount of I2 is liberated along with the formation white precipitate (of Cu2I2). This free iodine (I2), which remains in solution as [KI3] complex is then titrated with sodium thiosulphate solution using starch as indicator. At the end point of the titration, the blue colour of solution will disappear and a white precipitate of the Cu2I2 will remain in conical. The reactions that are taking place are:  

Keep practicing — related questions