B. A current in charges change direction
Explanation: an electric current that reverses its direction many times a second at regular intervals, typically used in power supplies.
Because its structure is drawn by dots which can't describ its structure.
<span>The equation that describes the problem is Fe(NO3)3(aq) + 3NaOH(aq) ---> Fe(OH)3(s) + 3 NaNO3(aq)
The Net ionic equation is written as follows:
Fe^3(aq) + 3NO3-(aq) + 3Na+(aq) + 3OH-(aq) ---> Fe(OH)3(s) + 3Na+(aq) + 3NO^3-(aq)</span>
Explanation:
Sodium has atomic number of 11 and its electronic configuration is given by:
![[Na]=1s^22s^22p^63s^1](https://tex.z-dn.net/?f=%5BNa%5D%3D1s%5E22s%5E22p%5E63s%5E1)
The nearest stable electronic configuration to sodium is of the neon. So, in order to attain stability of noble gas it will loose its single electron.

![[Na^+]=1s^22s^22p^63s^0](https://tex.z-dn.net/?f=%5BNa%5E%2B%5D%3D1s%5E22s%5E22p%5E63s%5E0)
Sodium has single valency that is 1.
Let nbe the valency of the ion 'X'
By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

So, the formulas for all the possible compounds that sodium can form with the other ions will be:

Answer: The answer is C
Explanation: Sound waves tend to spread farther the deeper the sound is, and the waves go lower then the second example, deeming it is louder.