When aluminum is produced by electrolysis we get 5.68 tons of aluminum and 5.04 tons of oxygen. What is the empirical formula of the compound that is being electrolyzed? (Hint 1 ton = 2000 lb and 1 lb = 454 g.)

Silver is electroplated at the cathode of an electrolysis cell by the half-reaction:

$$\mathrm{Ag}^{+}(a q)+\mathrm{e}^{-} \longrightarrow \mathrm{Ag}(s)$$

How many moles of electrons are required to electroplate $5.8 \mathrm{~g}$ of $\mathrm{Ag}$ ?

If the cost of electricity to produce magnesium by the electrolysis of molten magnesium chloride is $\$ 155$ per ton of metal, what is the cost (in dollars) of the electricity necessary to produce (a) $10.0$ tons of aluminum, (b) $30.0$ tons of sodium, (c) $50.0$ tons of calcium?

Electrolysis of molten $\mathrm{MgCl}_2$ is the final production step in the isolation of magnesium from seawater. Assuming that $45.6 \mathrm{~g}$ of $\mathrm{Mg}$ metal forms,
(a) How many moles of electrons are required?

Electrolysis of a metal nitrate solution $\mathrm{M}\left(\mathrm{NO}_3\right)_2(a q)$ for $325 \mathrm{~min}$ with a constant current of $20.0 \mathrm{~A}$ gives $111 \mathrm{~g}$ of the metal. Identify the metal ion $\mathrm{M}^{2+}$.

Chlorine gas is produced by the electrolysis of an aqueous solution of sodium chloride:

$$2 \mathrm{NaCl}(a q)+2 \mathrm{H}_2 \mathrm{O}(l) \stackrel{\text { electrolysis }}{2 \mathrm{NaOH}(a q)}+\mathrm{H}_2(g)+\mathrm{Cl}_2(g)$$

If the $\mathrm{H}_2(g)$ and $\mathrm{Cl}_2(g)$ from this reaction are collected separately at $10.0 \mathrm{~atm}$ and $25^{\circ} \mathrm{C}$, what volume of each can be obtained from $2.50$ kilograms of dissolved sodium chloride?

An aqueous solution of $\mathrm{Na}_2 \mathrm{~S}$ is placed in a beaker with two inert platinum electrodes. When the cell is attached to an external battery, electrolysis occurs.
Sulfur is the primary product at the anode. Write an equation for its formation.

Electrolysis of molten $\mathrm{NaCl}$ in a Downs cell is the major isolation step in the production of sodium metal. Assuming that $215 \mathrm{~g}$ of Na metal forms,
(c) How many amps will produce this amount in $9.50 \mathrm{~h}$ ?

If a water electrolysis cell opera tes at a current of 7.8 A, how long will it take to genera te 25.0 L of hydrogen gas at a pressure of 25.0 atm and a temperature of 25 $^{\circ} \mathrm{C}$?

What is the metal ion in a metal nitrate solution $\mathrm{M}\left(\mathrm{NO}_3\right)_3(a q)$ if $90.52 \mathrm{~g}$ of metal was recovered from a $4.00 \mathrm{~h}$ electrolysis at a constant current of $35.0 \mathrm{~A}$ ?

An unstirred solution of $2.00 \mathrm{M} \mathrm{NaCl}$ was electrolyzed for a period of $25.0 \mathrm{~min}$ and then titrated with $0.250 \mathrm{M}$ $\mathrm{HCl}$. The titration required $15.5 \mathrm{~mL}$ of the acid. What was the average current in amperes during the electrolysis?

The electrolysis of an aqueous solution of $\mathrm{NaCl}$ has the overall equation

$$2 \mathrm{H}_2 \mathrm{O}+2 \mathrm{Cl}^{-} \longrightarrow \mathrm{H}_2(g)+\mathrm{Cl}_2(g)+2 \mathrm{OH}^{-}(a g)$$

During the electrolysis, $0.228 \mathrm{~mol}$ of electrons pass through the cell. (a) How many electrons does this represent? (b) How many coulombs does this represent? (c) Assuming $100 \%$ yield, what masses of $\mathrm{H}_2$ and $\mathrm{Cl}_2$ are produced?

Predict the electrolysis products at the anode and cathode when the following are electrolysed:

a. molten aluminium iodide

b. a concentrated aqueous solution of magnesium chloride

c. a concentrated aqueous solution of sodium bromide

d. molten zinc oxide.

Metallic magnesium can be made by the electrolysis of molten $\mathrm{MgCl}_2$.

What mass of $\mathrm{Mg}$ is formed by passing a current of $5.25 \mathrm{~A}$ through molten $\mathrm{MgCl}_2$ for $2.50$ days?