Question

What volumes of H₂(g) and O₂(g) at STP are produced from the electrolysis of water by a current of 2.50 A in 15.0 min?

Short answer

The volumes of hydrogen and oxygen gas produced are 0.261 L and 0.13 L, respectively.

Step-by-step solution

Given Information

The time value is 15 min. Current value is 2.50 A.

Calculating moles of electrons released and hydrogen produced

The value can be substituted as:

$$\begin{gathered} Moles of electron=(15 \min )\left(\frac{60 s}{1 \min }\right)\left(\frac{2.5 C}{1 s}\right)\left(\frac{1 mol}{96485 C}\right) \\ =0.0233 mol e \end{gathered}$$

Finding the volume of hydrogen gas

The volume of hydrogen gas can be denoted as:

$$\begin{gathered} V=\frac{nRT}{P} \\ V=\frac{(0.01165 mol)(0.08206 L atm K^{-1} mo{l}^{-1})(273 K)}{1 atm} \\ V=0.261 L \end{gathered}$$

Calculating moles of electrons released and oxygen produced

The value can be substituted as:

$Moles of electron=(0.0233 mol )\left(\frac{1 mol O_2}{4 mol}\right)$

Finding the volume of oxygen gas

$$\begin{gathered} V=\frac{nRT}{P} \\ V=\frac{(0.005825 mol)(0.08206 L atm K^{-1} mo{l}^{-1})(273 K)}{1 atm} \\ V=0.13 L \end{gathered}$$