The answer is C3H8 and OCl2 they are molecular compounds. MgCl2 is an ionic compound while Zn(NO3)2 is an inorganic chemical compound.
Molecular compounds are covalent compounds in which the elements share electrons via covalent bonds. They are inorganic compounds that take the form of discrete molecules, for example water and carbon dioxide.
The number of H atoms in 3(NH₄)₂CrO₄ = 24
<h3>Further explanation </h3>
The empirical formula is the smallest comparison of atoms of compound forming elements.
A molecular formula is a formula that shows the number of atomic elements that make up a compound.
(empirical formula) n = molecular formula
Subscripts in the chemical formula indicate the number of atoms
The compound of 3(NH₄)₂CrO₄ ( 3 molecules of (NH₄)₂CrO₄ ) :
Number of H :

The polarity of a bond between two elements can be best determined by difference in the values of electronegativity.
<h3>Determination of polarity of bond</h3>
The polarity of a covalent bond can be determined by determining the difference in electronegativity between the two bonded atoms. Electronegativity is defined as the tendency of an atom to attract electrons to itself.
So we can conclude that the polarity of a bond between two elements can be best determined by difference in the values of electronegativity.
Learn more about polarity here: brainly.com/question/8229259
Answer:
The top branch-chain is a Isobutane branch. And the bottom branch chain is a Neopentane branch