Sunanda was experimenting with an electrolytic cell. She took an aqueous solution of
sodium chloride and added some zinc sulphate into it. When she dipped platinum
electrodes in the electrolyte and passed electric current through the solution the species
discharged at cathode and anode respectively were
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Answer:
CHEMISTRY
In electrolysis of NaCl when Pt electrode is taken then H
2
is liberated at the cathode while with Hg cathode it forms sodium amalgam, because:
December 26, 2019avatar
Tawqeer Reddy
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ANSWER
Sodium chloride in water dissociates as :
NaCl⇌Na
+
+Cl
−
H
2
O⇌H
+
+OH
−
When electric current is passed through this solution using platinum electrodes, Na
+
and H
+
move towards cathode and Cl
−
and OH
−
ions move towards anode.
If mercury is used as a cathode, H
+
ions are not discharged at mercury cathode because mercury has high hydrogen overvoltage. Na
+
ions are discharged at the cathode in preference of H
+
ions yielding sodium, which dissolves in mercury to form sodium amalgam.
Your answers are given below -:::::
Sodium chloride in water dissociates as :
NaCl⇌Na
+
+Cl
−
H
2
O⇌H
+
+OH
−
When electric current is passed through this solution using platinum electrodes, Na^+
and H ^+
move towards cathode and Cl
−
and OH ^-
ions move towards anode.
If mercury is used as a cathode, H ^+
ions are not discharged at mercury cathode because mercury has high hydrogen overvoltage. Na ^+
ions are discharged at the cathode in preference of H ^+
ions yielding sodium, which dissolves in mercury to form sodium amalgam.