The diagram shows a copper strip and a zinc strip in salt solution, connected through a bulb which lights. The more reactive metal is the negative electrode...
Question 1 Report
The diagram shows a copper strip and a zinc strip in salt solution, connected through a bulb which lights. The more reactive metal is the negative electrode where electrons leave. Which strip is the negative electrode?
Answer Details
A simple cell converts a reactivity difference into a voltage. The metal higher in the reactivity series loses electrons more readily, so it is the one that is oxidised, and the electrons it releases flow out through the external wire and light the bulb.
Zinc is above copper in the series, so zinc atoms dissolve as ions and leave electrons behind on the strip: \( \text{Zn} \rightarrow \text{Zn}^{2+} + 2\text{e}^{-} \). A build-up of electrons makes that strip the negative electrode, exactly as the question defines. The copper strip receives the electrons and is the positive electrode.
Do not choose copper because it is the better everyday conductor. In a cell, position in the reactivity series decides polarity, not conductivity.
Download The App On Google Playstore
Everything you need to excel in your exams
