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Multiple Bond Formation

Cd 2+ and C...

Question

${C d}^{2 +}$ and ${C u}^{2 +}$ are separated by complex formation using $K C N$ in which $K_{3} [{C u (C N)}_{4}]$ is more stable than $K_{4} [{C d (C N)}_{4}]$ ; on passing $H_{2} S$ gas $C d S$ is percipitated.

If the given statement is true enter 1, else enter 0.

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Solution

${C d}^{2 +}$ and ${C u}^{2 +}$ are separated by complex formation formation using $K C N$ in which. $K_{3} [{C u (C N)}_{4}]$ . is more stable than . $K_{4} [{C d (C N)}_{4}]$ ; on passing $H_{2} S$ gas. $C d S$ is percipitated.
$[C u (N H_{3})]_{4} S O_{4} + 10 K C N + 8 H_{2} O \to 2 K_{3} [C u (C N)_{4}] + 2 K_{2} S O_{4} + 8 N H_{4} O H + (C N)_{2}$
$[C d (N H_{3})]_{4} S O_{4} + 4 K C N + 4 H_{2} O \to K_{2} [C d (C N)_{4}] + K_{2} S O_{4} + 4 N H_{4} O H$
The second ionization of potassium cadmicyanide is higher than that of potassium cuprocyanide so that suffiient Cd (II) ions are present in solution. Hence, when hydrogen sulphide is passed, only CdS is precipitated.

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Similar questions

C u^{2 +}

C d^{2 +}

both are present, it is difficult to analyse. A scheme to analyse in a mixture is given below.
KCN forms complex with

C u^{2 +}

C d^{2 +}

C u^{2 +} + 2 C N^{-} ⟶ C u (C N)_{2}

C u (C N)_{2} ⟶ 2 C u C N ↓ + (C N)_{2}

C u C N + 3 K C N K_{3} C u (C N)_{4}] s t a b l e C d^{2 +} + K C N ⟶ K_{2} [C d (C N)_{4}] u n s t a b l e

H_{2} S

gas is passed, unstable complex of

C d^{2 +}

gives yellow ppt

[C d (C N)_{4}]^{2 -} ⇌ C d^{2 +} + 4 C N^{-}

C d^{2 +} + S^{2 -} ⟶ C d S y e l l o w ↓

If true enter 1, else enter 0.

{C u}^{2 +}

{C d}^{2 +}

solution is complexed by addition of

K C N S

. Reason: On passing

H_{2} S

gas stable complex

[{C u (C N)}_{4}]^{3 -}

is not affected.

Read the above assertion and reason and choose the corret option regarding it.

Q. Precipitation of

{C d}^{2 +}

{C u}^{2 +}

takes place in presence of dil.

H C l

H_{2} S

If the given statement is true enter 1, else enter 0.

Q. A reagent that can detect any of

{C u}^{2 +}, {F e}^{3 +}, {Z n}^{2 +}

{C d}^{2 +}

K_{4} [{F e (C N)}_{6}]

If the given statement is true enter 1 else enter 0.

K C N

(excess) is added to a

C u^{2 +}

, final species formed is

[C u (C N)_{4}]^{3 -}

If true enter 1, else enter 0.

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