Consider the following statements about Stainless Steel: 1. It contains Iron. 2. It contains Carbon. 3. It contains Chromium, Nickel, and Manganese. 4. It rusts easily in moist air. Which of the statements given above are correct?

Correct Option The correct option is (a). Explanation Stainless steel is an alloy of iron designed primarily to resist corrosion and oxidation. Unlike ordinary steel, it contains specific alloying elements that alter its chemical properties to prevent rusting. Statement-wise Analysis - Statement 1 is Correct: Iron is the base metal and the primary constituent of stainless steel. - Statement 2 is Correct: Carbon is added to the alloy (typically between 0.03% and 1.2%) to enhance hardness and tensile strength. Without carbon, the iron would be too soft for many structural applications. - Statement 3 is Correct: Stainless steel contains Chromium (minimum 10.5%), which is essential for corrosion resistance. Nickel and Manganese are often added to improve ductility, toughness, and workability. - Statement 4 is Incorrect: Stainless steel does not rust easily in moist air. The Chromium present in the alloy reacts with oxygen to form a thin, stable, and invisible passive layer of chromium oxide on the surface. This layer prevents further oxidation and protects the underlying metal from rusting. Key Takeaway: Stainless steel is an alloy of Iron, Carbon, Chromium, Nickel, and Manganese. Its resistance to rusting is primarily due to the formation of a protective Chromium Oxide layer.

NCERT Class 7 Science — Chapter 2: Physical and chemical changes

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Consider the following statements about Stainless Steel:

It contains Iron.
It contains Carbon.
It contains Chromium, Nickel, and Manganese.
It rusts easily in moist air.

Which of the statements given above are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A1, 2 and 3 only
B2, 3 and 4 only
C1 and 4 only
D1, 2, 3 and 4

Did you get this right?

Solution

Correct Option

The correct option is (a).

Explanation

Stainless steel is an alloy of iron designed primarily to resist corrosion and oxidation. Unlike ordinary steel, it contains specific alloying elements that alter its chemical properties to prevent rusting.

Statement-wise Analysis

Statement 1 is Correct: Iron is the base metal and the primary constituent of stainless steel.
Statement 2 is Correct: Carbon is added to the alloy (typically between 0.03% and 1.2%) to enhance hardness and tensile strength. Without carbon, the iron would be too soft for many structural applications.
Statement 3 is Correct: Stainless steel contains Chromium (minimum 10.5%), which is essential for corrosion resistance. Nickel and Manganese are often added to improve ductility, toughness, and workability.
Statement 4 is Incorrect: Stainless steel does not rust easily in moist air. The Chromium present in the alloy reacts with oxygen to form a thin, stable, and invisible passive layer of chromium oxide on the surface. This layer prevents further oxidation and protects the underlying metal from rusting.

Key Takeaway: Stainless steel is an alloy of Iron, Carbon, Chromium, Nickel, and Manganese. Its resistance to rusting is primarily due to the formation of a protective Chromium Oxide layer.

Your note

More from Chapter 2: Physical and chemical changes

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When the ash obtained from burning magnesium is dissolved in water, the resulting solution is:

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With reference to the reaction between Copper Sulphate and Iron, consider the following statements: 1. The colour of the solution changes from blue to green. 2. The green colour is due to the formation of Copper Oxide. 3. A brown deposit forms on the iron object, which is Rust (Iron Oxide). Which of the statements given above is/are correct?

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Which of the following pairs is correctly matched regarding the reaction of Copper Sulphate with Iron?

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With reference to the "Lime Water Test", consider the following statements: 1. It is a standard test for Carbon Dioxide gas. 2. The milky appearance is due to the formation of Calcium Oxide. 3. The chemical name of lime water is Calcium Hydroxide. Which of the statements given above is/are correct?

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Correct Option

The correct option is (a).

Explanation

Statement-wise Analysis

Statement 1 is Correct: Iron is the base metal and the primary constituent of stainless steel.
Statement 2 is Correct: Carbon is added to the alloy (typically between 0.03% and 1.2%) to enhance hardness and tensile strength. Without carbon, the iron would be too soft for many structural applications.
Statement 3 is Correct: Stainless steel contains Chromium (minimum 10.5%), which is essential for corrosion resistance. Nickel and Manganese are often added to improve ductility, toughness, and workability.
Statement 4 is Incorrect: Stainless steel does not rust easily in moist air. The Chromium present in the alloy reacts with oxygen to form a thin, stable, and invisible passive layer of chromium oxide on the surface. This layer prevents further oxidation and protects the underlying metal from rusting.

Key Takeaway: Stainless steel is an alloy of Iron, Carbon, Chromium, Nickel, and Manganese. Its resistance to rusting is primarily due to the formation of a protective Chromium Oxide layer.