Rydberg formula is given by:

where,
= Rydberg constant = 
= wavelength
and
are the level of transitions.
Now, for
= 2 and
= 6

= 
= 
= 
= 

= 
= 
= 
Now, for
= 2 and
= 5

= 
= 
= 

= 
= 
= 
Now, for
= 2 and
= 4

= 
= 
= 

= 
= 
= 
Now, for
= 2 and
= 3

= 
= 
= 

= 
= 
= 
It would have THREE rings/energy levels. This is because of the amount of electrons each orbital can hold.
\ i believe the word that you are looking for is lava
<h2>Acetic Acid</h2>
Explanation:
- Initial alcohol that is formed from methane is methanol that can be converted to acetic acid.
- Methanol in presence of
and hydrogen gas gets oxidized to acetic acid with the release of water.
Hence, compound A will be Acetic acid.
→ 
- The acetic acid formed can be transformed into -
→ 
The product formed is methane and carbon monoxide.
2.
→ 
The product formed is formaldehyde and water.
3.
→ 
The product formed is sodium acetate, carbon dioxide, and water.
The molar specific heat Cv = R s / 2
70.6 J/mol.K = (8.314 J/mol.K) * s / 2
So the number of degrees of freedom are:
s = 16.98 = 17