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 NH3is : -
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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