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Byju's Answer

Standard VIII

Chemistry

Reactivity Series

Copper contai...

Question

Copper containing alloy of weight $0.3175 g$ is dissolved in an acid and an excess of $K I$ is added. Estimation of copper in alloy is based on the following reactions:

$2 C u^{2 +} (a q) + 5 I^{-} (a q) \to C u_{2} I_{2} (s) + I_{3}^{-} (a q)$

${I_{3}}^{-} (a q) + 2 {S_{2} O_{3}}^{2 -} (a q) \to {S_{4} O_{6}}^{2 -} (a q) + 3 I^{-} (a q)$

Estimation is based on :

iodometry

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gravimetry

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Solution

The correct option is A iodometry
The estimation is based on iodometry. Because the iodometry involves indirect titration of iodine liberated by reaction with the analyte.
The liberated iodine is titrated against standard $N a_{2} S_{2} O_{3}$ solution.

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Similar questions

Copper containing alloy of weight

0.3175 g

is dissolved in an acid and an excess of

K I

is added. Estimation of copper in alloy is based on the following reaction:

2 C u^{2 +} (a q) + 5 I^{-} (a q) \to C u_{2} I_{2} (s) + I_{3}^{-} (a q)

{I_{3}}^{-} (a q) + 2 {S_{2} O_{3}}^{2 -} (a q) \to {S_{4} O_{6}}^{2 -} (a q) + 3 I^{-} (a q)

I_{2}

formed is converted to

K I_{3}

in the given reaction. This shows that

I_{2}

is :

Copper containing alloy of weight

0.3175 g

is dissolved in an acid and an excess of

K I

is added. Estimation of copper in alloy is based on the following reaction:

2 C u^{2 +} (a q) + 5 I^{-} (a q) \to C u_{2} I_{2} (s) + I_{3}^{-} (a q)

{I_{3}}^{-} (a q) + 2 {S_{2} O_{3}}^{2 -} (a q) \to {S_{4} O_{6}}^{2 -} (a q) + 3 I^{-} (a q)

Oxidising agent (

O

) and reducing agent (

R

) in the above reaction are :

2 C u^{2 +} (a q) + 5 I^{-} (a q) \to C u_{2} I_{2} (s) + I_{3}^{-} (a q)

{I_{3}}^{-} (a q) + 2 {S_{2} O_{3}}^{2 -} (a q) \to {S_{4} O_{6}}^{2 -} (a q) + 3 I^{-} (a q)

When copper containing alloy of weight

0.3175 g

is dissolved in an acid and an excess of

K I

is added,

25

mL of

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

is required, then Cu present in alloy is_________.

Q. After dissolving

0.20

g sample of the alloy in acid, an excess of

K I

is added and the

C u^{2 +}

and

I^{-}

ions undergo the reaction:

C u^{2 +} (a q) + I^{-} (a q) \to C u I (s) + I_{3}^{-} (a q)

I_{3}^{-} (a q) + S_{2} O_{3}^{2 -} (a q) \to S_{4} O_{6}^{2 -} (a q) + 3 I^{-} (a q)

20

ml of

0.1 M

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

is required for the titration to the equivalent point, what is the weight percent of

C u

in the alloy?

Q. The percentage of copper in a copper(II) salt can be determined by using a thiosulphate titration. 0.305 gm of a copper(II) salt was dissolved in water and added to an excess of potassium iodide solution liberating iodine according to the following equation.

2 C u^{2 +} (a q) + 4 I^{-} (a q) ⇌ 2 C u I (s) + I_{2} (a q)

The iodine liberated required

24.5 c m^{3}

of a

0.100 m o l e d m^{- 3}

solution of sodium thiosulphate

2 S_{2} {O_{3}}^{2 -} (a q) + I_{2} (a q) \to 2 I^{-} (a q) + S_{4} {O_{6}}^{2 -} (a q)

the percentage of copper, by mass in the copper(II) salt is:

[A t o m i c m a s s o f c o p p e r = 63.5]

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Copper containing alloy of weight 0.3175g is dissolved in an acid and an excess of KI is added. Estimation of copper in alloy is based on the following reactions: 2Cu2+(aq)+5I−(aq)→Cu2I2(s)+I−3(aq)I3−(aq)+2S2O32−(aq)→S4O62−(aq)+3I−(aq)Estimation is based on :

The correct option is A iodometryThe estimation is based on iodometry. Because the iodometry involves indirect titration of iodine liberated by reaction with the analyte.The liberated iodine is titrated against standard Na2S2O3 solution.

The correct option is A iodometry
The estimation is based on iodometry. Because the iodometry involves indirect titration of iodine liberated by reaction with the analyte.
The liberated iodine is titrated against standard $N a_{2} S_{2} O_{3}$ solution.