Use the problem below to answer the question: When a current is passed through a solution of salt water, sodium chloride decomposes according to the following reaction: NaCl + H2O → NaOH + Cl2 + H2 How many grams of chlorine gas, Cl2 are given off if 7.5 grams of sodium chloride, NaCl, are decomposed? Is this equation balanced?

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RomeliaThurston RomeliaThurston · Answer 1 · 2018-12-03T12:38:29+01:00

Answer: 4.544 grams of chlorine gas is produced in the given reaction.

Explanation: Number of moles can be calculated by using the formula:

[tex]Moles=\frac{\text{given mass}}{\text{Molar mass}}[/tex] ... (1)

Molar mass of NaCl = 58.5 g/mol

Given mass of NaCl = 7.5 grams

Moles of NaCl is calculated by:

[tex]Moles=\frac{7.5g}{58.5g/mol}[/tex]

Moles of NaCl = 0.128 moles

The given equation is not balanced. For any further calculation, we first need to balance the equation.

The balanced chemical equation follows:

[tex]2NaCl+2H_2O\rightarrow 2NaOH+Cl_2+H_2[/tex]

By Stoichiometry,

2 moles of NaCl produce 1 mole of chlorine gas

So, 0.128 moles of NaCl will produce = [tex]\frac{1}{2}\times 0.128[/tex] = 0.064 moles of chlorine gas

Mass of Chlorine gas is calculated by using equation 1, we get

Molar mass of [tex]Cl_2[/tex] = 71 g/mol

Putting the values in above equation, we get

[tex]0.064mol=\frac{\text{Given mass}}{71g/mol}[/tex]

Mass of [tex]Cl_2[/tex] produced = 4.544 grams