Water can be decomposed by electrolysis - Edexcel - GCSE Chemistry - Question 4 - 2011 - Paper 1
Question 4
Water can be decomposed by electrolysis. Hydrogen and oxygen are formed. This apparatus can be used to carry out the electrolysis.
(a) (i) Write the balanced equati... show full transcript
Worked Solution & Example Answer:Water can be decomposed by electrolysis - Edexcel - GCSE Chemistry - Question 4 - 2011 - Paper 1
Step 1
Write the balanced equation for water decomposing to form hydrogen and oxygen.
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Answer
The balanced equation for the electrolysis of water is:
ightarrow 2H_2 + O_2$$
Step 2
Describe the test to show that a gas is hydrogen.
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Answer
To test for hydrogen, you can use a lit splint. If hydrogen is present, it will ignite and produce a 'pop' sound.
Step 3
Describe the test to show that a gas is oxygen.
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The test for oxygen involves using a glowing splint. The glowing splint will reignite in the presence of oxygen, indicating its presence.
Step 4
Complete the sentence by putting a cross (X) in the box next to your answer.
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Answer
The toxic gas produced is:
☐ A hydrogen
☑ B chlorine
☐ C oxygen
☐ D carbon monoxide
Step 5
Give a safety precaution that should be taken when collecting this toxic gas.
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Ensure that the collection of chlorine gas is done in a well-ventilated area or under a fume hood to avoid inhalation.
Step 6
Give the name of the acid that must be used.
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The acid that must be used is hydrochloric acid (HCl).
