Answer:
A. Coefficients
Explanation:
that's the number in front of the molecules
Answer : The molecular formula of the compound will be, 
Explanation :
Empirical formula : It is the simplest form of the chemical formula which depicts the whole number of atoms of each element present in the compound.
Molecular formula : it is the chemical formula which depicts the actual number of atoms of each element present in the compound.
For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.
The equation used to calculate the valency is :

As we are given that the empirical formula of a compound is
and the molar mass of compound is, 90.09 gram/mol.
The empirical mass of
= 1(12) + 2(1) + 1(16) = 30 g/eq


Molecular formula = 
Thus, the molecular formula of the compound will be, 
Answer:The elements in the first column of the Periodic Table (other than hydrogen) are known as Group 1A metals, or alkali metals. When you compare the chemical properties of these elements (lithium, sodium, potassium, rubidium, cesium, and francium), what you'll notice is that they are all remarkably similar.
Explanation:
Acetic acid, phosphoric acid, hydrochloric acid.
sodium bicarbonate, magnesium hydroxide, aluminum hydroxide
calcium carbonate, sodium bicarbonate, magnesium sulfate.