Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.
In Activity 1.7, water is electrolyzed using carbon electrodes. Water (H₂O) contains hydrogen and oxygen in the ratio 2:1 by number of atoms. During electrolysis, water decomposes into hydrogen gas and oxygen gas.
The chemical composition of water shows that for every one oxygen atom, there are two hydrogen atoms. Therefore, when water undergoes electrolysis, the volume of hydrogen gas collected at one electrode is double the volume of oxygen gas collected at the other electrode.
The gas collected in double amount is hydrogen gas (H₂).
Explanation
The textbook context describes Activity 1.7 as electrolysis of water using carbon electrodes connected to a 6 volt battery. The reaction 2H₂(g) + O₂(g) → 2H₂O(l) shows that water contains hydrogen and oxygen in a 2:1 ratio. When electrolyzed, this ratio is reflected in the volumes of gases produced - hydrogen gas is collected in double the amount compared to oxygen gas.
Solution Steps
Step 1: Identify that Activity 1.7 involves electrolysis of water using carbon electrodes
Step 2: Note that water (H₂O) has 2 hydrogen atoms for every 1 oxygen atom
Step 3: Conclude that hydrogen gas is produced in double the amount compared to oxygen gas