The answer is B. In order to test something out you need to be able to solve it.
Answer:
C.
Explanation:
![\frac{1x10}x^{-14} = 1x10^{-9} \\ x =1x10^{-5} \\\\[OH][H]= 1x10^{-14}](https://tex.z-dn.net/?f=%5Cfrac%7B1x10%7Dx%5E%7B-14%7D%20%3D%201x10%5E%7B-9%7D%20%5C%5C%20x%20%3D1x10%5E%7B-5%7D%20%5C%5C%5C%5C%5BOH%5D%5BH%5D%3D%201x10%5E%7B-14%7D)
The concetration can be found by dividing the water ph constant by the [H=] or [OH] to find the other
Answer:
Only
gives spontaneous reaction.
Explanation:
A redox reaction will be spontaneous if standard reduction potential (
) of the reaction is positive. Because it leads to negative standard gibbs free energy change (
), which is a thermodynamic condition for spontaneity of a reaction.

Where
and
represents standard reduction potential of reduction half cell and standard reduction potential of oxidation half cell.
(1) Oxidation:
; 
Reduction:
; 
So, 
Hence this pair will give spontaneous reaction.
(2) Similarly as above, 
Hence this pair will give non-spontaneous reaction.
(3) Similarly as above, 
Hence this pair will give non-spontaneous reaction.
(4) Similarly as above, 
Hence this pair will give non-spontaneous reaction.
Hey there!:
Molar mass N₂ = 28.0134 g/mol
28.0134 g ------------------- 22.4 L (at STP )
mass N₂ -------------------- 50.0 L
mass N₂ = 50.0 x 28.0134 / 22.4
mass N₂ = 1400.67 / 22.4
mass N₂ = 62.529 g
Hope this helps!