Molar conductivities (Λom) at infinite dilution of NaCl, HCl an

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251.

Using the Gibbs energy change, ΔG0 = +63.3 KJ for the following reaction,
Ag2CO3 (s) r2Ag+ (aq) + CO32- (aq)
the Ksp of Ag2CO3 (s) in water at 250 C is (R= 8.314 JK-1 mol-1)

  • 3.2 x 10-26

  • 8.0 x 10-12

  • 2.9 x 10-3

  • 2.9 x 10-3

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252.

At 250 molar conductance of 0.1 molar aqueous solutions of ammonium hydroxide is 9.54 ohm-1 cm2 mol-1 and at infinite dilution, its molar conductance is 238 ohm-1 cm2 mol-1. The degree of ionisation of ammonium hydroxide at the same concentration and temperature is 

  • 2.080%

  • 20.800%

  • 4.008%

  • 4.008%

2130 Views

253.

A button cell used in watches functions as following
Zn space left parenthesis straight s right parenthesis space plus Ag subscript 2 straight O space left parenthesis straight s right parenthesis space plus straight H subscript 2 straight O space left parenthesis straight l right parenthesis space rightwards harpoon over leftwards harpoon space 2 space Ag space left parenthesis straight s right parenthesis space plus Zn to the power of 2 plus end exponent space left parenthesis aq right parenthesis space plus 2 OH to the power of minus space left parenthesis aq right parenthesis
If space half minus cell space potentials space are
Zn to the power of 2 plus end exponent space left parenthesis aq right parenthesis space plus 2 straight e to the power of minus space rightwards arrow space Zn left parenthesis straight s right parenthesis semicolon space straight E to the power of 0 equals space minus 0.76 space straight V
Ag subscript 2 straight O space left parenthesis straight s right parenthesis space plus straight H subscript 2 straight O space left parenthesis straight l right parenthesis space plus 2 straight e to the power of minus rightwards arrow 2 Ag space left parenthesis straight s right parenthesis space plus 2 OH to the power of minus space left parenthesis aq right parenthesis space left parenthesis straight E to the power of 0 space equals space 0.34 space straight V right parenthesis
The cell potential will be

  • 1.10 V

  • 0.42 V

  • 0.84 V

  • 0.84 V

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254.

Limiting molar conductivity  of NH4OH (i.e., straight capital lambda with straight o on top subscript m left parenthesis N H subscript 4 O H right parenthesis space end subscript is equal to 

  • straight capital lambda with straight o on top subscript m space left parenthesis N H subscript 4 C l right parenthesis space end subscript space plus straight capital lambda with straight o on top subscript m space left parenthesis N a C l right parenthesis space end subscript minus space straight capital lambda with straight o on top subscript m space left parenthesis N a O H l right parenthesis space end subscript
  • straight capital lambda with straight o on top subscript m space left parenthesis N a O H right parenthesis space end subscript space plus straight capital lambda with straight o on top subscript m space left parenthesis N a C l right parenthesis space end subscript minus space straight capital lambda with straight o on top subscript m space left parenthesis N H subscript italic 4 C l right parenthesis space end subscript
  • straight capital lambda with straight o on top subscript m space left parenthesis N H subscript 4 O H right parenthesis space end subscript space plus straight capital lambda with straight o on top subscript m space left parenthesis N H subscript italic 4 C l right parenthesis space end subscript minus space straight capital lambda with straight o on top subscript m space left parenthesis HCl right parenthesis space end subscript
  • straight capital lambda with straight o on top subscript m space left parenthesis N H subscript 4 O H right parenthesis space end subscript space plus straight capital lambda with straight o on top subscript m space left parenthesis N H subscript italic 4 C l right parenthesis space end subscript minus space straight capital lambda with straight o on top subscript m space left parenthesis HCl right parenthesis space end subscript
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255.

Standard reduction potentials of the half-reactions are given below.

F2 (g) +2e- → 2F- (aq) ;  Eo = +2.85 V
Cl2 (g) +2e- →2Cl- (aq) ; Eo = +1.36V
Br2 (l) +2e- → 2Br(aq) ; Eo = +1.06 V
I2 (s) +2e- →2I- (aq); Eo = +0.53 V

The strongest oxidising and reducing agents respectively are

  • F2 and I-

  • Br2 and Cl-

  • Cl2 and Br-

  • Cl2 and Br-

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256.

Molar conductivities (Λom) at infinite dilution of NaCl, HCl and CH3COONa are 126.4, 425.9 and 91.0 S Cm2 mol-1 respectively. Λom for CH3COOH will be

  • 425.5 S cm2 mol-1

  • 180.5 S cm2 mol-1

  • 290.8 S cm2 mol-1

  • 290.8 S cm2 mol-1


D.

290.8 S cm2 mol-1

CH3COONa +HCl → NaCl + CH3COOH
91 + 425.9 = 126.4 + x
x= 516.9 -126.4
= 390.5 S cm2 mol-1

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257.

The Gibb's energy for the decomposition of Al2O3 at 500o C is as follow
2/3 Al2O→ 4/3 Al + O2;
ΔrG = +960 kJ mol-1
The potential difference needed for the electrolytic reduction aluminium oxide (Al2O3) at 5000 C is at least 

  • 4.5 V

  • 3.0 V

  • 2.5 V

  • 2.5 V

3145 Views

258.

Standard electrode potential of three metal X, Y and Z are -1.2 V, +0.5 V and -3.0 V respectively. The reducing power of these metals will be

  • Y > X > Z

  • Z> X> Y

  • X > Y > Z

  • X > Y > Z

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259.

If the Eocell for a given reaction has a negative value then which of the following gives the correct relationships for the values of ΔGo and Keq ?

  • ΔGo < 0; Keq > 1

  • ΔGo < 0; Keq < 1

  • ΔGo > 0; Keq < 1

  • ΔGo > 0; Keq < 1

1145 Views

260.

The electrode potentials for 

Cu2+ (aq) + e- → Cu+ (aq) and Cu+ (aq) + e- →Cu (s)

are +0.15 V and +0.50V respectively. The value of straight E subscript bevelled Cu to the power of 2 plus end exponent over Cu end subscript superscript straight o will be 

  • 0.325 V 

  • 0.650 V

  • 0.150 V

  • 0.150 V

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