I think the answer is b because that is true
E
θ
Cell
=
+
2.115
l
V
Cathode
Mg
2
+
/
Mg
Anode
Ni
2
+
/
Ni
Explanation:
Look up the reduction potential for each cell in question on a table of standard electrode potential like this one from Chemistry LibreTexts. [1]
Mg
2
+
(
a
q
)
+
2
l
e
−
→
Mg
(
s
)
−
E
θ
=
−
2.372
l
V
Ni
2
+
(
a
q
)
+
2
l
e
−
→
Ni
(
s
)
−
E
θ
=
−
0.257
l
V
The standard reduction potential
E
θ
resembles the electrode's strength as an oxidizing agent and equivalently its tendency to get reduced. The reduction potential of a Platinum-Hydrogen Electrode under standard conditions (
298
l
K
,
1.00
l
kPa
) is defined as
0
l
V
for reference. [2]
A cell with a high reduction potential indicates a strong oxidizing agent- vice versa for a cell with low reduction potentials.
Two half cells connected with an external circuit and a salt bridge make a galvanic cell; the half-cell with the higher
E
θ
and thus higher likelihood to be reduced will experience reduction and act as the cathode, whereas the half-cell with a lower
E
θ
will experience oxidation and act the anode.
E
θ
(
Ni
2
+
/
Ni
)
>
E
θ
(
Mg
2
+
/
Mg
)
Therefore in this galvanic cell, the
Ni
2
+
/
Ni
half-cell will experience reduction and act as the cathode and the
Mg
2
+
/
Mg
the anode.
The standard cell potential of a galvanic cell equals the standard reduction potential of the cathode minus that of the anode. That is:
E
θ
cell
=
E
θ
(
Cathode
)
−
E
θ
(
Anode
)
E
θ
cell
=
−
0.257
−
(
−
2.372
)
E
θ
cell
=
+
2.115
Indicating that connecting the two cells will generate a potential difference of
+
2.115
l
V
across the two cells.
Answer:

Explanation:
Here, we want to know the number of atoms of each of the elements present in the given term
For the Barium, it is only affected by the external 2, so we have 2 Barium atoms only
For oxygen, we have a set in OH and another in H2O. For the OH own, we have 2 oxygen atoms and for the H2O , we have 8 atoms. That makes a total of 10, which when multiplied by the first 2 outside, gives 20
For Hydrogen, we have two sets, one with OH and the other with H2O
For the one with OH, we have 2 while for the one with H2O, we have 16. That makes a total of 18 which when multiplied by 2 gives a total of 36
Thus, we have each of the elements and their counts as follows:
Barium = 2
Oxygen = 20
Hydrogen = 36
Mathematically:

Thus:
Answer:
Lets Write Down the Given Initial Conditions.



In Order to Solve for the Unknown: 
we must use the Ideal Gas Law to Solve for the Second Unknown pressure:

Then Rearrange this equation in a form where P2 can be solved from:

Then Insert the Values from above to solve:

The Answer is : 1830 mmHg considering sig figs