Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
The reactivity series is a list of metals arranged in the order of their decreasing chemical activities. Metals at the top are most reactive, while those at the bottom are least reactive.
A more reactive metal displaces a less reactive metal from its salt solution. This is known as a displacement reaction: , where is more reactive than .
Metals above hydrogen in the series can displace hydrogen from dilute acids (like and ) to produce hydrogen gas ().
Highly reactive metals like and react vigorously with cold water to form hydroxides and , whereas moderately reactive metals like , , and only react with steam to form oxides.
Metals like , , and are found at the bottom of the series; they are chemically noble and do not react easily with water or dilute acids.
Hydrogen, though a non-metal, is included in the series because it can lose an electron to form a positive ion (), similar to metals.
📐Formulae
💡Examples
Problem 1:
What will be observed when an iron nail is placed in a solution of copper(II) sulfate ()? Write the chemical equation.
Solution:
Observations: The blue color of the solution fades and turns light green (), and a reddish-brown deposit of copper is formed on the iron nail.
Explanation:
Iron () is more reactive than copper () as per the reactivity series. Therefore, iron displaces copper from its salt solution.
Problem 2:
Why is sodium () kept immersed in kerosene oil?
Solution:
Explanation:
Sodium is a highly reactive metal. It reacts vigorously with the oxygen and moisture present in the air to catch fire. To prevent accidental fires and its reaction with air/moisture, it is stored in kerosene.