Number of moles =

so to calculate molar mass (Molecular weight of compound):
Molecular weight =

=

= 50 g / mole
Now we calculate molecular weight of each compound in choices:
a) C₂H₄O = 44
b) CO₂ = 44
c) CH₃Cl = 50.4 ALMOST 50 so this is the correct answer
d) C₂H₆ = 30
Na is cation so it loses electron to be positive and become stable losing one valence shells one electron so it's oxidation number is +1 ie A is correct
Answer:
trigonal pyramidal
Explanation:
In NF3, the nitrogen atom is sp3 hybridized. Now we must remember that according to the VSEPR theory, the number of electron pairs in the valence shell of the central atom in a molecule determines its shape.
Here, the nitrogen atom is the central atom and its outermost shell is surrounded by four electron pairs - one lone pair and three bond pairs. This means that it has a tetrahedral electron pair geometry.
However, due to the lone pair, the three fluorine atoms are arranged in a trigonal pyramidal geometry. Hence the correct shape of the molecule is trigonal pyramidal.