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Science (086) — AI-generated practice question

AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.

Q1. [1] medium thorough-understanding
Pure iron is too soft and corrodes easily, so it is alloyed to make stainless steel. Which of the following correctly identifies the elements added and the primary properties they impart? (A) Nickel and copper — to increase malleability and electrical conductivity (B) Carbon and chromium — to increase hardness and resistance to corrosion (C) Carbon and manganese — to lower melting point and increase lustre (D) Chromium and copper — to increase ductility and make it lighter
  1. A To increase its melting point and make it lustrous
  2. B To make it hard and resistant to corrosion
  3. C To increase its electrical conductivity and ductility
  4. D To make it lighter and more malleable
Generated by claude-sonnet-4-6 · 2026-06-26 01:06 · grounding rag
Model Answer

(B) Carbon and chromium — to increase hardness and resistance to corrosion

When iron is mixed with nickel and chromium, we get stainless steel, which is hard and does not rust.

Explanation

The textbook (Section 3.5) explicitly states: "if it is mixed with a small amount of carbon (~0.05%), it becomes hard and strong. When iron is mixed with nickel and chromium, we get stainless steel, which is hard and does not rust." Option (B) is the closest correct match — carbon increases hardness and chromium provides corrosion resistance. Examiners expect you to link the alloying elements directly to the properties they impart.

Previous-year CBSE Grade 10 board exam questions, organised by subject and chapter, each with a model answer — free to read and print.