A.fluoride
Fluoride helps to prevent tooth decay
<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.
<h2>Ultraviolet Light</h2>
Explanation:
- The energy of a photon that will be released if an electron falls from the n= 2 orbit (excited state) to the n0 = 1 orbit (ground state) is of ultraviolet light.
- In the ultraviolet part of the spectrum, a photon having an energy of 10.2 eV has a wavelength of 1.21 x 10-7 m.
- Hence, when an electron wants to jump or it gets excited from the first level to the second level that is from n = 1 orbit to n = 2 orbits, it must absorb a photon of ultraviolet light.
- But,When an electron falls from n = 2 orbit to n = 1 orbit or from n = 2 orbit(excited state) to n = 0 orbit(groubd state), it emits a photon of ultraviolet light.
