Equal masses (1.00 g) of three Group 1 metals—lithium, sodium, and potassium—are reacted completely with excess water in three separate open beakers. Which of the following statements correctly compares the observations or chemical outcomes of these reactions?
Lithium produces the greatest total volume of hydrogen gas because it has the lowest relative atomic mass of the three metals, resulting in the highest number of moles of metal reacting.
Potassium reacts the fastest because it has the highest first ionisation energy of the three metals, allowing it to lose its outer electron most easily.
Sodium produces the greatest total volume of hydrogen gas because its intermediate reactivity allows a more stable and complete reaction with water.
Lithium reacts the fastest of the three metals because it has the most negative standard electrode potential (E∘=−3.04 VE^\circ = -3.04\text{ V}E∘=−3.04 V), making the reaction thermodynamically most favourable.
Practise Edexcel GCSE Chemistry Group 1 with exam-style questions for Foundation and Higher tier. 51 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
