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A compound contains 24.27% C, 4.07% H and 71.65% Cl. The molar mass is about 99g.

What is the molecular formula ?

1 Answer

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Answer:

Molecular formula = C₂H₄Cl₂

Step-by-step explanation:

Empirical formula:

It is the simplest formula gives the ratio of atoms of different elements in small whole number .

Molecular formula:

Molecular formula consist of symbols of elements present in compound with numbers of atoms of each element in subscript.

Given data:

Percentage of hydrogen = 4.07%

Percentage of carbon = 24.27%

Percentage of Cl = 71.65%

Molar mass = 99 g/mol

Molecular formula = ?

Solution:

Number of gram atoms of H = 4.07 / 1.01 = 4.0

Number of gram atoms of Cl = 71.65 / 35.5 = 2.0

Number of gram atoms of C = 24.27 / 12 = 2.0

Atomic ratio:

C : H : Cl

2/2 : 4/2 : 2/2

1 : 2 : 1

C : H : Cl = 1 : 2 : 1

Empirical formula is CH₂Cl.

Molecular formula:

Molecular formula = n (empirical formula)

n = molar mass of compound / empirical formula mass

empirical formula mass = 12+1×2+ 35.5 = 49.5

n = 99/49.5

n = 2

Molecular formula = n (empirical formula)

Molecular formula = 2 ( CH₂Cl)

Molecular formula = C₂H₄Cl₂

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