Stainless steel is an alloy made up of

Analysis

The question asks for the composition of stainless steel, which is a common alloy in Chemistry. To answer this, we must identify the primary metallic components that give stainless steel its characteristic resistance to corrosion and rust.

Concept

An alloy is a mixture of two or more elements, where at least one is a metal. Stainless steel is a specific type of steel designed to resist oxidation. While all steel contains iron and a small amount of carbon, "stainless" steel is specifically defined by the addition of chromium. Chromium reacts with oxygen to form a thin, invisible layer of chromium oxide on the surface, which prevents further rusting of the iron underneath.

Solution

1. Identify the base: All steels are primarily composed of Iron (Fe).
2. Identify the key additive: The "stainless" property is provided by Chromium (Cr). Typically, stainless steel contains at least 10.5% chromium.
3. Evaluate the options: • A (Iron and zinc): This describes galvanized iron, not stainless steel. • B (Copper and tin): This is the composition of bronze. • C (Iron and chromium): This is the correct definition of the primary components of stainless steel (often with small amounts of nickel and carbon added). • D (Iron and carbon): This is the definition of plain carbon steel.

Conclusion

Stainless steel is primarily an alloy of iron and chromium. While carbon is present in small amounts in almost all steel, the defining characteristic that makes it "stainless" is the chromium content. Therefore, option C is the most accurate description among the choices provided.

Exam Tip: Remember the mnemonic "Stainless = Chromium." Whenever you see a question about stainless steel, look for Chromium in the options. If you see "Iron and Carbon," that is just regular steel; the Chromium is what makes it "stainless."