I believe the correct answer from the choices listed above is option B. A chemical formula written above or below the yield sign indicates <span>that the substance is used as a catalyst. I am certain with this answer. Hope this helps. Have a nice day.</span>
Answer:
: conjugate acid of 
: conjugate base of 
: conjugate base of
: conjugate acid of
Explanation:
According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.
Here in forward reaction is accepting a proton, thus it is considered as a base and after accepting a proton, it forms which is a conjugate acid.
And is losing a proton, thus it is considered as an acid and after loosing a proton, it forms which is a conjugate base.
Similarly in the backward reaction, is loosing a proton, thus it is considered as a acid and after loosing a proton, it forms which is a conjugate base.
And is accepting a proton, thus it is considered as a base and after accepting a proton, it forms 
which is a conjugate acid.
Since transition metals with partially filled d orbitals have color when in solution. Therefore which ever solution has some color will likely contain a transition metal with a partially filled d orbital.
an example of this is solution with Cu²⁺ will have a blue tint to it.
they move around and eventually come and join to make a solid
