Answer : The volume of 4.9 M
stock solution used to prepare the solution is, 12.24 ml
Solution : Given,
Molarity of aqueous
solution = 1.20 M = 1.20 mole/L
Volume of aqueous
solution = 50.0 ml = 0.05 L
(1 L = 1000 ml)
Molarity of
stock solution = 4.9 M = 4.9 mole/L
Formula used :

where,
= Molarity of aqueous
solution
= Molarity of
stock solution
= Volume of aqueous
solution
= Volume of
stock solution
Now put all the given values in this formula, we get the volume of
stock solution.

By rearranging the term, we get

Therefore, the volume of 4.9 M
stock solution used to prepare the solution is, 12.24 ml
In response to your question, the kind of energy the skier has is called potential energy.
4Na +2e- ---->2Na2
O2 +2e- ------>2O
<span>That would be compound!
Compounds are pure substances, which consists of two or more elements chemically combined in a fixed proportion by mass. Compounds have definite proportion.</span>