Which scientist first discovered and isolated the chemical element potassium using electrolysis?

Introduction / Context:
Many metallic elements were first isolated in the nineteenth century using the newly developed technique of electrolysis. This question asks about the discovery of potassium, which was first isolated by Sir Humphry Davy. Being able to connect each element with its discoverer is useful for general science and chemistry based general knowledge questions.

Given Data / Assumptions:
• The element in focus is potassium.
• Options are Humphry Davy, Alan Turing, Bill Gates, and Tim Berners-Lee.
• The learner is expected to distinguish between a nineteenth century chemist and late twentieth century computer scientists and entrepreneurs.

Concept / Approach:
The approach is straightforward. Humphry Davy pioneered electrolysis and isolated several alkali and alkaline earth metals, including potassium and sodium. Alan Turing is a mathematician and computer science pioneer. Bill Gates is a software entrepreneur, and Tim Berners-Lee invented the World Wide Web. By matching each name with the correct field, the only candidate who fits the chemical discovery of potassium is Davy.

Step-by-Step Solution:
Step 1: Focus on potassium, an alkali metal, and think of early electrolysis experiments.
Step 2: Recall that Humphry Davy used a voltaic pile to isolate potassium from molten caustic potash, marking the first time the metal was obtained in pure form.
Step 3: Recognise that Alan Turing is famous for code breaking and theoretical computer science, not for chemical discoveries.
Step 4: Remember that Bill Gates co founded Microsoft and is associated with personal computing, not nineteenth century chemistry.
Step 5: Note that Tim Berners-Lee developed the World Wide Web, a network technology entirely separate from elemental discovery.

Verification / Alternative check:
To verify, recall that most chemistry textbooks mention Davy's isolation of potassium in 1807 from caustic potash and present it as a classic example of electrolysis. None of the other listed individuals have any role in this part of scientific history. The strong mismatch between modern computing figures and a basic chemical discovery confirms that Humphry Davy is the correct answer.

Why Other Options Are Wrong:
Alan Turing, Bill Gates, and Tim Berners-Lee all belong to the world of computing and information technology. They lived more than a century after the period in which many basic chemical elements were first isolated. Therefore, it is impossible for them to have discovered potassium. Their names serve as clear distractors and should be eliminated when solving the question.

Common Pitfalls:
This question is generally easy, but a small pitfall is that learners may not remember the exact list of metals discovered by Davy. Even if you forget details, you can still solve the question by observing that the other three names are clearly modern computing figures. To strengthen your preparation, however, it is recommended to memorise that Davy isolated sodium, potassium, calcium, strontium, and several other metals using electrolysis.

Final Answer:
The scientist who discovered potassium is Humphry Davy.