I think the correct answer from the choices listed above is option A. The additional piece of information needed to determine the molecular formula would be percent composition of carbon. A molecular formula is <span>a formula that gives the number of atoms of each of the elements present in one molecule of a specific compound.</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:

<span>b) earths outer iron core
</span><span>A coil of wire that is carrying a current and produces a magnetic field is called a solenoid. So the correct option is option "B", in regards to the question given. The term solenoid was first invented by the famous French physicist named Andre-Marie Ampere. In the terms of a physicist, it indicates a coil that has a far greater lenth than the diameter and is wrapped around a core made of metal to create a uniform magnetic field. If a compass is brought near the wire through which current is passing, it will indicate the direction in which the current is flowing. </span>
Answer: bromine.
Bromine is described as a red or red - brown or reddish - brown element and you can find some pictures in textbooks or internet that reflect this color, both as a gas and as a liquid.
When mixed with some organic clear solvents it produces a beautifull red mixture.