My Birthday is in April, So, electron of H atom is in n=4( pfund series).
Ionisation Energy= +13.6(z^2/n^2)
= +13.6(1/16)
= +0.85 eV
The answer is letter D. Reactants, Products
"As we move through the visible spectrum of violet, blue, green, yellow, orange and red, the wavelengths become longer. The range of wavelengths (400 - 700 nm) of visible light is centrally located in the electromagnetic spectrum (Fig. 1)."
-https://www.asu.edu/courses/phs208/patternsbb/PiN/rdg/color/color.shtml
Methanoic acid has a molecular formula of HCOOH, when form an ester it's HCOO-, so the rest of the ester is -C4H9, a saturated 4 carbon chain. As shown in the attached diagram, there are 4 structural isomers, and the third isomer has 2 stereoisomers. So the answers is D:5.
The shape of the molecule is trigonal planar.
For example, H₂O:
..
O
/ \
H H