Boron can undergo the following reactions with the given enthalpy changes :
`2B(s)+(3)/(2)O_(2)(g)rarrB_(2)O_(3)(s),” “DeltaH=-1260 ” kJ”`
`2B(s)+3H_(2)(g)rarrB_(2)H_(6)(g),” “DeltaH=30 ” kJ”`
Assume no other reactions are occuring.
If in a container (operating at constant pressure) which is isolated from the surrounding, mixture of `H_(2)` (gas) and `O_(2)` (gas) are passed over excess of B(s), then calculate the molar ratio `(O_(2) : H_(2))` so that temperature of the container do not change :
A. `15 : 3`
B. `42 : 1`
C. `1 : 42`
D. `1 : 84`
`2B(s)+(3)/(2)O_(2)(g)rarrB_(2)O_(3)(s),” “DeltaH=-1260 ” kJ”`
`2B(s)+3H_(2)(g)rarrB_(2)H_(6)(g),” “DeltaH=30 ” kJ”`
Assume no other reactions are occuring.
If in a container (operating at constant pressure) which is isolated from the surrounding, mixture of `H_(2)` (gas) and `O_(2)` (gas) are passed over excess of B(s), then calculate the molar ratio `(O_(2) : H_(2))` so that temperature of the container do not change :
A. `15 : 3`
B. `42 : 1`
C. `1 : 42`
D. `1 : 84`
Correct Answer – D
No. of moles of `O_(2)` required to supplied 30 kJ heat to second reaction
`=(30)/(1260)xx(3)/(2)=(1)/(28)`
`Son_(O_(2)):n_(H_(2))=(1)/(28):3 ” or “1 : 84`