Answer:
In the 1H NMR spectrum of ethanol three different signals are observed, this is due to the existence of 3 types of hydrogens with different chemical environment. Hydrogens A (3.57 ppm) are more screened than C (1.10 ppm) due to the presence of oxygen (electonegative atom that removes electron density). The chemical environment of hydrogen B (4.78 ppm), attached directly to oxygen, is also different by resonating at a frequency different from the previous ones.

The hydroxylic hydrogen produces a singlet, the pair of carbon hydrogens one give rise to a quadruplet and the three hydrogens of carbon two produce a triplet.
Explanation:
Answer: 2 C2H4 + 6 O2 => 4 CO2 + 4 H2O
Explanation:The coefficient are as follows: 2: 6: 4: 4
Each atom on the reactant and product side are equal.
Reactant Product
C 2x2 = 4 4x1 = 4
H 2x4 = 8 4x2 = 8
O 6x2 = 12 (4x2) + 4 = 12
When a electron moves from higher shell to lower shell ,it releases energy because if it goes to lower shell without releasing energy then it will unable to do that so.as lower electron shells have low energy electrons