1 ) pH of
0.005 M of H2SO4 is : -
A ) 2 , B
) 6 ,
C ) 7 , D
) None of these ,
Correct
Answer : - A ) 2 ,
Solution
: -
H2SO4 is
strong acid .
H2SO4 ----------> 2H+ + 1SO-4 .
H2SO4 =
0.005 M ,
So , 2H+ = 2 (
0.005 ) = 0.01 M .
pH = -
log [ H+ ] = - log [ 0.01 ] = - log [ 10^(-2) ] ,
pH = 2 (
1 ) =
2 , Answer .
2 )
Volume of CH4 (methane) is 100 cm3
and volume of H2 ?
CH4 +
H2O --------> 3H2 + CO .
A ) 100
cm3 , B
) 300 cm3 ,
C ) 438
cm3 , D
) None of these ,
Correct
Answer : - B ) 300 cm3 ,
Solution
: -
1 dm3 =
1000 cm3 .
So ,
volume of CH4 ( methane ) = 100 cm3
= 0.1 dm3 .
So moles
of methane = volume / dm3 = 0.1
/ 22.4 M .
So , as
by given reaction in question : -
1 M of
CH4 gives 3 M
of H2 .
So , ( 0.1 / 22.4 ) M of
CH4 gives 3( 0.1 / 22.4 ) M of H2
.
So ,
volume of H2 = moles x STP .
Volume of
H2 =
3( 0.1 / 22.4 ) x 22.4 ,
Volume of
H2 =
0.3 dm3 = 300
cm3 ,
Answer .
3 )
Oxidation number of sulpher in sulphuric acid ( H2SO4 ) : -
A ) + 3 , B
) – 4 ,
C ) + 6 , D
) None of these ,
Correct
Answer : - C ) + 6 ,
4 )
Oxidation number of N in NH3
is : -
A ) - 3 , B
) – 4 ,
C ) + 6 , D
) None of these ,
Correct
Answer : - A ) - 3 ,
5 ) Proton : -
Charge :
- Protons have + 1
charge .
Ionization
energy : - Proton is already charged ,
so cannot break more .
Radius :
- Proton has very small radius .
Hydration
energy : - Proton is easily dissolved or
attracted by water , so hydration energy is very large .
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