Explanation:
The given data is as follows.
Volume = 1 L, Concentration of Ca = 5 ppm or 5 mg/L
As 1 mg = 0.001 g so, 5 mg /L will be equal to 0.005 g/l. Molar mass of calcium is 40.078 g/mol.
Hence, calculate molarity of calcium as follows.
Molarity of Ca = 
= 
Molarity of Ca = 
Hence, molarity of 
is . Since, volume is same so, moles of calcium chloride will be 
.
Thus, we can conclude that mass of will be as follows.
(molar mass of = 110.984 g/mol)
= 0.0138 g
Thus, we can conclude that mass of is 0.0138 g.
Answer:
D. Ni²⁺
Explanation:
We know at once that the answer cannot be A or C, because Ni and Cu are already in their lowest oxidation states.
The correct answer must be either B or D.
An electrolytic cell is the opposite of a galvanic cell. In the former, the reaction proceeds spontaneously. In the latter, you must force the reaction to occur.
One strategy to solve this problem is:
- Look up the standard reduction potentials for the half reaction·
- Figure out the spontaneous direction.
- Write the equation in the reverse direction.
1. Standard reduction potentials
E°/V
Cu²⁺ + 2e⁻ ⟶ Cu; 0.3419
Ni²⁺ + 2e⁻ ⟶ Ni; -0.257
2. Galvanic Cell
We reverse the direction of the more negative half cell and add.
<u>E°/V
</u>
Ni ⟶ Ni²⁺ + 2e⁻; 0.257
<u>Cu²⁺ + 2e⁻ ⟶ Cu; </u> 0.3419
Ni + Cu²⁺ ⟶ Cu + Ni²⁺; 0.599
This is the spontaneous direction.
Cu²⁺ is reduced to Cu.
3. Electrochemical cell
<u>E°/V</u>
Ni²⁺ + 2e⁻ ⟶ Ni; -0.257
<u>Cu ⟶ Cu²⁺ + 2e⁻; </u> <u>-0.3419</u>
Cu + Ni²⁺ ⟶ Ni + Cu²⁺; -0.599
This is the non-spontaneous direction.
Ni²⁺ is reduced to Ni in the electrolytic cell.
that would have to be nucleus
Tell the teacher, do NOT clean it up yourself.
The first one would be the best answer
