I'll go with B, have a good day
A) 1s on H and 3p on Cl
In HCl, the H atom has only one valance electron. Each share an electron an therefore a single covalent bond is formed between the two. The bond in HCl is therefore a result of an overlap between 1s orbital and ONLY ONE of the lobes of the 3p orbital of Chlorine.
To convert the mass of a compound to formula units, the conversion factor is Avogadro's number, 6.022 x10^23 formula units/ mol and its molar mass. In this case, we are given with 19.0 grams of magnesium chloride which has a mass of 95.21 g/mol. Hence the answer is 1.20 x 10^23 formula units.
A serial dilution is the stepwise dilution of a substance in solution. Usually the dilution factor at each step is constant, resulting in a geometric progression of the concentration in a logarithmic fashion.
