Question

Bleach is often added to a wash to remove stains from clothes, The active ingredient in bleach is sodium hypochlorite (NaClO). A bleach solution can be prepared by bubbling chlorine gas into a solution of sodium hydroxide to produce liquid water and an aqueous solution of sodium hypochlorite and sodium chloride. A typical bottle of bleach has a volume of$1.42\mathrm{gal}$, with a density of$1.08\mathrm{g}/\mathrm{mL}$and contains $282\mathrm{g}$of $\mathrm{NaClO},(6.2,6.3,7.4,7.8,8.6,9.4)$

a. Is sodium hypochlorite an ionic or a molecular compound?

b. What is the mass/volume percent $(\mathrm{m}/\mathrm{v})$of sodium hypochlorite in the bleach solution?

c. Write a balanced chemical equation for the preparation of a bleach solution.

d. How many liters of chlorine gas at STP are required to produce one bottle of bleach?

Short answer

(Part a)

Sodium hypochlorite has an ionic bond between ${\mathrm{Na}}^{+}$and ${\mathrm{ClO}}^{*}$ions. For this reason, this is an ionic compound

(Part b)

Therefore, the mass/volume percent (m/v) of sodium hypochlorite in the bleach solution is $5.25\%$(m/v)

(Part c)

The balanced chemical equation of the reaction is as follows:

${\mathrm{Cl}}_2(\mathrm{g})+2\mathrm{NaOH}\left(\mathrm{aq}\right)⟶\mathrm{NaCl}\left(\mathrm{aq}\right)+\mathrm{NaClO}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

(Part d)

Therefore,$84.9\mathrm{L}$of chlorine gas at STP are required to produce one bottle of bleach.

Step-by-step solution

Given information (Part a)

That are given sentences are :

Calculate the mass of sodium hypochlorite$\left(\mathrm{NaClO}\right)$

Explanation 

Given volume of bleach solution is$1.42\mathrm{gal}$

Convert gal to$\mathrm{mL}$is as follows:

$$\begin{gathered} =1.42\mathrm{gal}\times \frac{3785.41\mathrm{mL}}{1\mathrm{gal}} \\ =5375.3\mathrm{mL} \end{gathered}$$

Density of bleach solution $=1.08\mathrm{g}/\mathrm{mL}$

Calculate the mass of sodium hypochloritelocalid="1652772295803" $\left(\mathrm{NaClO}\right)$in the bleach solution is localid="1652772304900" $282\mathrm{g}$.

Given information (Part a)

That are given sentences are : (Part a)

Sodium hypochlorite

Explanation (Part a)

(a)

Sodium hypochiorite has an ionic bond between ${\mathrm{Na}}^{+}$and $\mathrm{ClO}°$ions. For this reason, this is an ionic compound

Given information (Part b)

That are given equations are : (b)

Calculate the mass by volume percent by using the following expression.

Explanation (Part b)

Calculate the mass by volume percent by using the following expression.

$$\begin{gathered} \text{Mass percent}(\mathrm{m}/\mathrm{v})=\frac{\text{Solute mass}}{\text{Solution volume}}\times 100\% \\ =\frac{282\mathrm{g}}{5375.3\mathrm{mL}}\times 100\% \\ =5.25\% \end{gathered}$$

Therefore, the mass/volume percent (m/v) of sodium hypochlorite in the bleach solution is$5.25\%$$(\mathrm{m}/\mathrm{v})$

Given information (Part c)

That are given equations are : (c)

A bleach solution is prepared by bubbling chlorine gas

Explanation (Part c)

(c)

A bleach solution is prepared by bubbling chlorine gas into a solution of sodium hydroxide to produce liquid water and an aqueous solution of sodium hypochlorite and sodium chloride. The balanced chemical equation of the reaction is as follows:

${\mathrm{Cl}}_2(\mathrm{g})+2\mathrm{NaOH}\left(\mathrm{aq}\right)⟶\mathrm{NaCl}\left(\mathrm{aq}\right)+\mathrm{NaClO}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{I}\right)$

Given information (Part d)

That are given equations are : (d)

Calculate the moles of sodium hypochlorite in the bleach solution are as follows:

Explanation (d)

The balanced reaction is,

${\mathrm{Cl}}_2(\mathrm{g})+2\mathrm{NaOH}\left(\mathrm{aq}\right)⟶\mathrm{NaCl}\left(\mathrm{aq}\right)+\mathrm{NaClO}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

Mass of sodium hypochiorite in the bleach solution is$282\mathrm{g}$.

Calculate the moles of sodium hypochlorite in the bleach solution are as follows:

$$\begin{gathered} \text{Moles}=\frac{\text{mass of}\mathrm{NaClO}}{\text{Molar mass of}\mathrm{NaClO}} \\ =\frac{282\mathrm{g}}{74.44\mathrm{g}/\mathrm{mol}} \\ =3.79 \end{gathered}$$

According to the balance chemical equation,

Mole ratio of ${\mathrm{Cl}}_2$and $\mathrm{NaClO}$are in$1:1$ ratio.

Given information 

That are given sentences are :

Therefore, volume occupied by $3.79$moles of Cl2 gas at STP is,

Explanation 

So, moles of chlorine gas required are$3.79$
moles.

At STP, volume occupied by 1 mole of $\mathrm{Cl}2$gas is $22.4\mathrm{L}$

Therefore, volume occupied by$3.79$moles of Cl2 gas at STP is,

$$\begin{gathered} =3.79\mathrm{mol}\times \frac{22.4\mathrm{L}}{1\mathrm{mol}} \\ =84.9\mathrm{L} \end{gathered}$$

Therefore,$84.9\mathrm{L}$of chlorine gas at STP are required to produce one bottle of bleach.