Which of the following is not true about empirical and molecular formulas? (1 point)
the molecular formula of a compound can be the same as its empirical formula.
the molecular formula of a compound can be the same whole-number multiple of its empirical formula.
several compounds can have the same empirical formula, but have different molecular formulas.
the empirical formula of a compound can be triple its molecular formula.

 Option 4:

The empirical formula of a compound can be triple its molecular formula.

This option is wrong.

Explanation:

Empirical Formula :

Empirical formula is the simplest ration of atoms in the molecule but not all numbers of atoms in a compound.  

Example:

The formula unit of a sugar = C₆H₁₂O₆

The whole numbers of atoms in this compound

C = 6

H = 12

O = 6

The Empirical formula is its simplest ratio

                    C : H : O

                    6 : 12 : 6

                    1 : 2 : 1

So the empirical formula of sugar is = CH₂O

Molecular formula:

The Chemical formula of a compound that show the total composition of compound and show the total numbers of atoms in a compound.

Example:

molecular formula of sulfuric acid = H₂SO₄

That the as a whole it have 2 hydrogen one sulfur and 4 oxygen.

Now to investigate for the right option:

option 1:

The molecular formula of a compound can be the same as its empirical formula.

This option is correct.

Example

if we look at formula of CH₄

It already have the simplest ratio as will as the formula of its original composition.

                     Molecular Formula : Empirical Formula

                                          CH₄       :       CH₄

Option 2:

The molecular formula of a compound can be the same whole-number multiple of its empirical formula.

This option is also correct.

Example

As we look at the empirical formula of Sugar that is CH₂O

and it if we multiply it with whole number it will give its molecular formula that is C₆H₁₂O₆

Empirical Formula =  (CH₂O)

Molecular Formula :  6 x  Empirical Formula    

Molecular Formula :  C₆H₁₂O₆

Option 3:

Several compounds can have the same empirical formula, but have different molecular formulas.

This option is correct.

Several compounds have same emperical formula but different molecular formula

Example

if we look or the same empirical formula of sugar it can be the imperical formula of othe compound to.

For Sugar:

6 x empirical formula

6 (CH₂O)

C₆H₁₂O₆

For Sedoheptulose

7 x empirical formula

7 (CH₂O)

C₇H₁₄O₇

So both have same empirical formula but different molecular formula.

Option 4:

The empirical formula of a compound can be triple its molecular formula.

This option is wrong.

as empirical formula is the simplest ratio of atoms in a compound it couldn't be triple of a molecular formula.

Example

CH₂O is empirical formula of sugar that is not triple of the molecular formula C₆H₁₂O₆

first one is the correct answer