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Which of the following metals are obtained by electrolysis of their chlorides in molten state?
(i) Na
(ii) Ca
(iii) Fe
(iv) Cu
(a) (i) and (iv)
(b) (iii) and (iv)
(c) (i) and (iii)
(d) (i) and (ii)

Answers (1)

Ans. (d)
Sodium (Na) and calcium (Ca) being highly reactive are obtained by electrolysis of their chlorides in molten state.
During electrolysis of NaCl
NaCl\rightarrow Na^{+}\left ( l \right )+Cl^{-}\left ( l \right )
At cathode: reduction of 2Na^{+}\left ( aq \right )+e^{-}\rightarrow Na\left ( s \right )
At anode: oxidation of 2Cl^{-}\left ( aq \right )\rightarrow Cl_{2}\left ( g \right )+2e^{-}

Net Reaction: 2Na^{+}\left ( aq\right )+2Cl^{-}\left ( aq \right )\rightarrow 2Na\left ( s \right )+Cl_{2}\left ( g \right )

During electrolysis of aqueous CaCl2
We have,
At anode: 2Cl^{-}\rightarrow Cl_{2}+2e^{-}

At anode: Ca^{2+}+2e^{-}\rightarrow Ca(s)

Therefore option (D) is correct

 

 

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