Which of the following reacts with concentrated sulphuric acid? (a) \(\mathrm{Pb}\) (b) \(\mathrm{Pt}\) (c) \(\mathrm{Ag}\) (d) \(\mathrm{Au}\)

When we talk about the interaction between metals and concentrated sulphuric acid (H2SO4), we're delving into a chemical process that combines the acid's strong oxidizing properties and the ability of certain metals to be oxidized. Concentrated sulphuric acid can donate oxygen to reactive metals, allowing them to lose electrons and form metal sulphate and hydrogen gas.

However, not all metals will react in the same way. The outcome depends on where the metals stand in the reactivity series—a ranking of metals based on their willingness to participate in chemical reactions. Typically, if a metal is positioned above hydrogen in this series, it can be oxidized by concentrated sulphuric acid. This reaction is an important experimental distinction for classifying metals' reactivity.

Metal reactivity refers to the ease with which a metal can undergo a chemical reaction. This property is pivotal in understanding how different metals will behave when encountering an oxidizing agent like concentrated sulphuric acid. The reactivity series is a practical tool used by chemists to predict the outcomes of reactions involving metals.

The series ranks metals from the most reactive, like potassium, to the least reactive, known as noble metals. Highly reactive metals can displace hydrogen from acids, a clear indication of their eagerness to lose electrons and form positive ions. It's this very ability to lose electrons that is exploited in various industrial applications, from metal extraction to the manufacturing of batteries.

Noble metals, such as gold (Au), silver (Ag), and platinum (Pt), stand out due to their remarkable resistance to corrosion and chemical reactions. They’re found toward the bottom of the reactivity series. Their inert nature arises from their reluctance to lose electrons and form compounds.

Noble metals don't easily react with concentrated sulphuric acid, remaining unaltered when other metals might corrode or dissolve. This unreactivity allows noble metals to maintain their luster and structural integrity over time, making them highly prized in jewelry making and electronic components. Their stable nature also makes them valuable in fields that require materials that won't react under harsh conditions, such as space exploration and medical implants.

An oxidizing agent is a substance that can accept electrons from another species during a chemical reaction, thus getting reduced in the process. Concentrated sulphuric acid is an excellent example of a powerful oxidizing agent; it tends to pull electrons away from reactants, allowing it to transform metals into their oxidized states.

Oxidizing agents play a crucial role in redox reactions—a fundamental class of reactions involving the transfer of electrons. In industry, oxidizing agents are used for processes such as purifying water, bleaching paper, and processing minerals. Understanding their behavior helps predict how different substances might interact under various conditions, influencing how we use and handle these chemicals in the lab and beyond.