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Byju's Answer

Standard XII

Chemistry

SHE

Excess of KI ...

Question

Excess of KI reacts with $C u S O_{4}$ solution and then $N a_{2} S_{2} O_{3}$ solution is added to it. Which of the statement is incorrect for this reaction?

C u_{2} I_{2}

is formed

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C u I_{2}

is formed

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N a_{2} S_{2} O_{3}

is oxidised

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Evolved

I_{2}

is reduced

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Solution

The correct option is B $C u I_{2}$ is formed
Copper sulphate reacts with potassium iodide to form cuprous iodide and iodine.
$2 C u S O_{4} + 4 K I \to C u_{2} I_{2} ↓ + I_{2} + 2 K_{2} S O_{4}$
Thus, $C u I_{2}$ 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.
$2 N a_{2} S_{2} O_{3} + I_{2} \to N a_{2} S_{4} O_{6} + 2 N a I$
Iodine is reduced and sodium thiosulphate is oxidized.

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Similar questions

Excess of KI reacts with $C u S O_{4}$ solution and then $N a_{2} S_{2} O_{3}$ solution is added to it. Which of the following statement is incorrect from this reaction

C u S O_{4}

reacts with excess amount of

K I

followed by solution of

N a_{2} S_{2} O_{3}

. In this process which of the following statement is correct?

2.5

g sample of copper is dissolved in excess of

H_{2} S O_{4}

to prepare

100

ml of

0.02 M C u S O_{4} (a q)

10

ml of

0.02 M

solution of

C u S O_{4} (a q)

is mixed with excess of

K I

to show the following changes:

C u S O_{4} + 2 K I ⟶ K_{2} S O_{4} + C u I_{2}

2 C u I_{2} ⟶ C u_{2} I_{2} + I_{2}

The liberated iodine is titrated with hypo (

N a_{2} S_{2} O_{3}

) which requires

V

ml of

0.1 M

hypo solution for its complete reduction.The amount of

I_{2}

liberated in the reaction of

10

ml of

0.02 M

solution with excess

K I

is :

2.5

g sample of copper is dissolved in excess of

H_{2} S O_{4}

to prepare

100

ml of

0.02 M C u S O_{4} (a q)

10

ml of

0.02 M

solution of

C u S O_{4} (a q)

is mixed with excess of

K I

to show the following changes:

C u S O_{4} + 2 K I ⟶ K_{2} S O_{4} + C u I_{2}

2 C u I_{2} ⟶ C u_{2} I_{2} + I_{2}

The liberated iodine is titrated with hypo (

N a_{2} S_{2} O_{3}

) which requires

V

ml of

0.1 M

hypo solution for its complete reduction.

The color of the solution developed during the addition of

K I

C u S O_{4}

solution is :

2.5

g sample of copper is dissolved in excess of

H_{2} S O_{4}

to prepare

100

ml of

0.02 M C u S O_{4} (a q)

10

ml of

0.02 M

solution of

C u S O_{4} (a q)

is mixed with excess of

K I

to show the following changes:

C u S O_{4} + 2 K I ⟶ K_{2} S O_{4} + C u I_{2}

2 C u I_{2} ⟶ C u_{2} I_{2} + I_{2}

The liberated iodine is titrated with hypo (

N a_{2} S_{2} O_{3}

) which requires

V

ml of

0.1 M

hypo solution for its complete reduction.

Percentage of purity of sample is:

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Excess of KI reacts with CuSO4 solution and then Na2S2O3 solution is added to it. Which of the statement is incorrect for this reaction?

Excess of KI reacts with $C u S O_{4}$ solution and then $N a_{2} S_{2} O_{3}$ solution is added to it. Which of the statement is incorrect for this reaction?