Question

Which of the coordination compounds (i) to (v) are used for the following processes :
A: Electroplating
B: Removal of excess copper from human body
C: Estimation of hardness of water
(i) DMG (ii) \( Na_2EDTA \) (iii) Cis-platin (iv) D-penicillamine (v) \( K[Au(CN)_2] \)

• A. \( A = iv,\; B = i,\; C = iii \)
• B. \( A = i,\; B = iii,\; C = iv \)
• C. \( A = v,\; B = iv,\; C = ii \)
• D. \( A = iii,\; B = ii,\; C = i \)

Hint:

Remember common applications of coordination compounds: \( K[Au(CN)_2] \) for gold electroplating, EDTA for hardness of water, D-penicillamine for copper removal, and cis-platin as anticancer drug.

Answer 1

The Correct Option is C

Step 1: Identify the compound used in electroplating.
Electroplating of gold is commonly carried out using complex cyanide salts of gold.
Potassium dicyanoaurate(I), \( K[Au(CN)_2] \), is used for gold electroplating because it provides a stable soluble gold complex.
So:
\[ A = v \]

Step 2: Identify the compound used for removal of excess copper from human body.
D-penicillamine is a chelating agent.
It binds excess copper ions in the body and helps in their removal.
It is used in Wilson's disease, where copper accumulation occurs in the body.
So:
\[ B = iv \]

Step 3: Identify the compound used for estimation of hardness of water.
Hardness of water is mainly due to \( Ca^{2+} \) and \( Mg^{2+} \) ions.
\( Na_2EDTA \) forms stable complexes with \( Ca^{2+} \) and \( Mg^{2+} \).
Therefore, \( Na_2EDTA \) is used in complexometric titration for estimation of hardness of water.
So:
\[ C = ii \]

Step 4: Check the remaining compounds.
DMG is used mainly for detection or estimation of \( Ni^{2+} \) ions.
Cis-platin is an anticancer coordination compound.
Thus, these do not match the given processes.

Step 5: Write the complete matching.
From the above analysis:
\[ A = v,\quad B = iv,\quad C = ii \]

Step 6: Match with given options.
The matching \( A = v,\; B = iv,\; C = ii \) corresponds to option (C).

Step 7: Conclusion.
Thus, the correct answer is:
\[ \boxed{A = v,\; B = iv,\; C = ii} \]