A harbour authority tests two backup power units for navigation lights.
A rechargeable battery is initially flat. Its charger is switched off part-way through recharging.
A hydrogen/oxygen fuel cell has its hydrogen supply stopped while oxygen continues to be supplied. The hydrogen supply is later restored.
Four statements are made about the test.
Statement 1: Interrupting the charging process makes the battery unable to produce any potential difference.
Statement 2: The battery can power the lights for less time than it could after a complete recharge.
Statement 3: While the hydrogen supply is stopped, oxygen alone keeps the fuel cell operating.
Statement 4: After the hydrogen supply is restored, the fuel cell does not need a charging current before it can produce a potential difference again.
Which statements are correct?
2 and 3 only
2 and 4 only
1 and 4 only
1 and 3 only
131 exam-style questions on OCR GCSE Chemistry 6.2 Organic chemistry, covering 6.2.1 Crude oil and fractional distillation, 6.2.2 Cracking and dependence on hydrocarbons, 6.2.3 Functional groups and homologous series, 6.2.4 Reactions of alkanes, alkenes and alcohols, 6.2.5 Addition polymerisation and repeat units, 6.2.6 Naturally occurring polymers, 6.2.7 Chemical cells and fuel cells, and 6.2.8 Condensation polymerisation and how to make one. Each one has a worked solution and a mark scheme showing where the marks go.