Answer:
The correct order it b. always add acid last.
Explanation:
Adding acid first could result on a violent reaction and heat or fumes can be generated. The best approach is to always add all the water or non-acid component first, or add a significant portion before adding the acid slowly to the mixture.
Moles of electrons:
The moles of electrons that are transferred are 12F
A balanced equation:
2 moles of Aluminium metal react with excess copper(II) nitrate.

Given:
Moles of Aluminium = 2
As Aluminium goes from 0 to +3 oxidation state

And copper goes from +2 to 0

On balancing the number of electrons we get:
For 1 mole of Al
is required.
Therefore for 2 moles of Al,
Total
F mole of electrons
Where F= Faraday's constant= 96500 C
So, 12F moles of electrons are transferred.
Learn more about Faraday's Law here,
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Answer: A
Explanation: Protons and neutrons form the nucleus of the atom, with electrons orbiting it.
It can be easily judged that only the first reaction is an acid base reaction among the three given in the question. So, we can avoid the other two reactions given in the question. Now let us focus and write down the balanced chemical equation of <span>P-Toluidine + HCl.
</span><span>C7H9N + HCl = C7H10N (+) + Cl (-)
</span>
I hope the answer has come to your help.
You can use P1V1/T1 = P2V2/T2 but since pressure is constant is becomes V1/T1=V2/T2
V1=0.5 L
T1=203 K
T2=273 K
V2=unknown
0.5L/203 = V2/273
V2= 0.67 L so C
Hope this helps :)