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during electrolysis of AgNO3 loss of Ag in the anode compartment was 0.589g in a voltmeter connected in series 1.259g Ag was deposited.Find transport number of Ag+ and NO3-ions |
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Answer» Answer: After electrolysis: ∵20.09g of anodic solution contained 0.06227 g of AgNO 3
∴ Mass of water in solution =20.09−0.06227=20.02773g Thus, 20.02773gH 2
O has 0.06277 g AgNO 3
= 170 0.06227
equivalentAgNO 3
=0.0003663equivalentAgNO 3
or Ag +
Before Electrolysis: ∵10.0g of solution contained 0.01788 g AgNO 3
∴ Mass of water in solution =10−0.01788=9.98212g Thus, 9.98212 g water has =0.01788 gAgNO 3
= 170 0.01788
eq. AgNO 3
∴20.02773g water has = 170×9.98212 0.01788×20.02773
eq. AgNO 3
=0.000211 equivalent of AgNO 3
or Ag +
Thus, increase in concentration of Ag + during electrolysis =0.0003663−0.000211 =0.0001553 equivalent Also, Mass of Cu deposited in coulometer =0.009479 g ∴ Equivalent of Cu deposited in coulometer = 31.8 0.009479
∴ Equivalent of Cu deposited or actual increase around anodic solution =0.0002981 eq. (Since, equal equivalents are discharged at either ELECTRODE) Since, Ag + had MIGRATED from anode, which BRINGS a fall in concentration around anode but DUE to attacked electrodes, (i.e., Ag in AgNO 3
), apparent increase is noticed. Thus, fall in concentration of Ag + around anode = Actual increase which would have occur around anode - Apparent increase in Ag + around anode =0.0002981−0.0001553 =0.0001428 equivalent of Ag +
∴ Transport no. of t Ag +
= Eq. OFCU + deposited in coulometer Eq. ofAg + lost in anodic cell
= 0.0002981 0.0001428
t Ag +
=0.479≈5 Now, t Ag +
+l NO 3 −
=1 ∴t NO 3 −
=1−0.4792=0.521≈5 Answer |
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