1
JEE Main 2018 (Offline)
MCQ (Single Correct Answer)
+4
-1
Change Language
How long (approximate) should water be electrolysed by passing through 100 amperes current so that the oxygen released can completely burn 27.66 g of diborane?
(Atomic weight of B = 10.8 u)
A
1.6 hours
B
6.4 hours
C
0.8 hours
D
3.2 hours
2
JEE Main 2018 (Online) 15th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
When an electric currents passed through acidified water, 112 mL of hydrogen gas at N.T.P. was collected at the cathode in 965 seconds. The current passed, in ampere, is :
A
1.0
B
0.5
C
0.1
D
2.0
3
JEE Main 2017 (Online) 9th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
To find the standard potential of M3+/M electrode,the following cell is constituted : Pt/M/M3+(0.001 mol L−1 )/Ag+(0.01 mol L−1 )/Ag

The emf of the cell is found to be 0.421 volt at 298 K. The standard potential of half reaction M3+ + 3e$$ \to $$ M at 298 K will be :

(Given $$E_{A{g^ + }\,/\,Ag}^ - $$ at 298 K = 0.80 Volt)
A
0.38 Volt
B
0.32 Volt
C
1.28 Volt
D
0.66 Volt
4
JEE Main 2017 (Online) 8th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Change Language
What is the standard reduction potential (Eo) for Fe3+ $$ \to $$ Fe ?
Given that :
Fe2+ + 2e$$-$$ $$ \to $$ Fe; $$E_{F{e^{2 + }}/Fe}^o$$ = $$-$$0.47 V
Fe3+ + e$$-$$ $$ \to $$ Fe2+; $$E_{F{e^{3 + }}/F{e^{2 + }}}^o$$ = +0.77 V
A
$$-$$ 0.057 V
B
+ 0.057 V
C
+ 0.30 V
D
$$-$$ 0.30 V
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