Question

Aluminum reacts with chlorine gas to produce aluminum chloride according to the following equation. Al + Cl2 → AlCl3 Which of the following fractions can be used for the mole ratio to determine the mass of Cl2 from a known mass of AlCl3?

A. 2/1

B. 3/2

C. 1/2

D. 2/3

Answer 1

Answer : The correct option is, (B) 3/2

Explanation :

The given chemical reaction is,

`Al+Cl_2\rightarrow AlCl_3`

This reaction is an unbalanced chemical reaction because in this reaction number of aluminum and chlorine atoms are not balanced.

In order to balance the chemical equation, the coefficient '2' put before the
`Al` and
`AlCl_3` and the coefficient '3' put before the
`Cl_2` and we get the balanced chemical equation.

The balanced chemical reaction will be:

`2Al+3Cl_2\rightarrow 2AlCl_3`

From the balanced chemical reaction we conclude that,

As, 2 moles of
`AlCl_3` produced from 3 moles of
`Cl_2`

So, 1 mole of
`AlCl_3` produced from
`(3)/(2)` moles of
`Cl_2`

Thus, the fractions used for the mole ratio to determine the mass of
`Cl_2` from a known mass of
`AlCl_3` can be,
`(3)/(2)`.

Answer 2

Answer;

B. 3/2

Explanation;

Balance the chemical equation

2Al + 3Cl2 → 2AlCl3

We want to convert moles of AlCl3 to moles of Cl2

The conversion factor is 2 mol AlCl3/3 mol Cl2.

We choose the one that makes the units cancel:

x mol AlCl3 x (3 mol Cl3)/(2mol AlCl3) = x mol Al

The fraction for the molar ratio is 3/2.