Question

State whether the given statement is true or false:
A compound of relative molecular mass $34$ and empirical formula $HO$ has the molecular formula ${{H}_{2}}{{O}_{2}}$ .
A.True
B.False

Answer 1

Before talking about the answer, firstly you should know the relationship between molecular formula and empirical formula. Empirical formula is the positive integer ratio of atoms and molecular formula is the way from which we describe chemical proportions of atoms.
Formula used: $MF=n\times EF$
where, $MF$ is the molecular formula, $EF$ is the empirical formula and $n$ is the number by which the simplest ratio of empirical formula is obtained.

Complete step by step answer:
Here, it is given that the molecular mass of the compound is $34$
The empirical formula mass of $HO$ is $1+16=17$
We know that ,
Molecular formula, $MF=n\times EF$
$34=n\times 17 \\\ n=2 \\\$
Here, the molecular mass of ${{H}_{2}}{{O}_{2}}$ is $2\times 1+2\times 16=34$
Therefore, the correct option is (A) True, which states that a compound of relative molecular mass of $34$ and empirical formula $HO$ has the molecular formula ${{H}_{2}}{{O}_{2}}$ .

Additional Information:
-Empirical formula is also defined as the ratio of atoms present in a different element in a molecule. From this formula, we can also calculate the percentage composition of a compound.
Let us take some examples to understand empirical formulas easily.
-The empirical formula of sulphur monoxide is $SO$ and for sulphur dioxide, it is again $SO$ .
-The empirical formula of ethylene $({{C}_{2}}{{H}_{4}})$ contains two atoms of carbon and four atoms of hydrogen, so its empirical formula is $C{{H}_{2}}$ .
-Molecular formula is defined as the integer multiple of empirical formula.

Note:
The $SI$ unit of molecular mass is kilogram per mole$(kg/mole)$ .
Molecular formula tells us about the number of atoms of each element present in a molecule whereas the empirical formula is defined as the reduced ratio of elements in the compound.
The molecular mass ${{H}_{2}}{{O}_{2}}$ is $34$