1
AIEEE 2009
+4
-1
In a fuel cell methanol is used as fuel and oxygen gas is used as an oxidizer. The reaction is
CH3OH(l) + 3/2O2 $$\to$$ CO2 (g) + 2H2O (l)
At 298K standard Gibb’s energies of formation for CH3OH(l), H2O(l) and CO2 (g) are -166.2, -237.2 and -394.4 kJ mol−1 respectively. If standard enthalpy of combustion of methanol is -726 kJ mol−1, efficiency of the fuel cell will be
A
87%
B
90%
C
97%
D
80%
2
AIEEE 2008
+4
-1
Given $$E_{C{r^{3 + }}/Cr}^o$$ = -0.72 V; $$E_{Fe^{2+}/Fe}^o$$ = -0.42V, The potential for the cell Cr | Cr3+ (0.1M) || Fe2+ (0.01 M) | Fe is
A
0.26 V
B
0.399 V
C
−0.339 V
D
−0.26 V
3
AIEEE 2007
+4
-1
The equivalent conductances of two strong electrolytes at infinite dilution in H2O (where ions move freely through a solution) at 25oC are given below:
$$\wedge _{C{H_3}COONa}^o$$ = 91.0 S cm2/equiv
$$\wedge _{HCl}^o$$ = 426.2 S cm2/equiv
What additional information/quantity one needs to calculate $$\wedge ^o$$ of an aqueous solution of acetic acid?
A
$$\wedge ^o$$ of chloroacetic acid (C/CH2COOH)
B
$$\wedge ^o$$ of NaCl
C
$$\wedge ^o$$ of CH3COOK
D
The limiting equivalent conductance of $${H^ + }( \wedge _{{H^ + }}^o)$$
4
AIEEE 2007
+4
-1
The cell, Zn | Zn2+ (1M) || Cu2+ (1M) | Cu($$E_{cell}^o$$ = 1.10V) was allowed to be completely discharged at 298 K. The relative concentration of Zn2+ to Cu2+ $$\left[ {{{\left[ {Z{n^{2 + }}} \right]} \over {\left[ {C{u^{2 + }}} \right]}}} \right]$$ is
A
antilog (24.08)
B
37.3
C
1037.3
D
9.65 $$\times$$ 104
EXAM MAP
Medical
NEET