Alloys and Their Uses – NDA Chemistry PYQs

Solve NDA Chemistry previous-year questions on Alloys and their Uses with detailed solutions and explanations.

Chapter-wise PYQs • Concept-based explanations • Exam insights

NDA 2023-II

Q. 1. Which one of the following alloys contains a non-metal as one of its constituent ?

(a) Brass

(b) Bronze

(d) Steel

Answer: (d) Steel

Explanation: Steel is an alloy of iron (Fe) and carbon (C). Carbon is a non-metal. Brass = Cu + Zn (both metals). Bronze = Cu + Sn (both metals). Amalgam = mercury + another metal (all metals). Concept Tested: Steel contains carbon – a non-metal as alloy constituent

★ JOVIK Exam Insight: Steel = Fe + C. Carbon is a non-metal, making steel unique among common alloys as it contains a non-metal.

Q. 2. Which one of the following metal is NOT an essential component in stainless steel ?

(a) Iron

(b) Nickel

(d) Tin

Answer: (d) Tin

Explanation: Stainless steel contains iron (Fe) as the base metal, with chromium (Cr) to provide corrosion resistance, and often nickel (Ni) for added toughness. Tin is not an essential component of stainless steel. Concept Tested: Composition of stainless steel – Fe, Cr, Ni (not Sn)

NDA 2022-II

Q. 3. Bronze is an alloy of

(a) Cu and Zn

(b) Cu and Sn

(d) Fe and Cu

Answer: (b) Cu and Sn

Explanation: Bronze is an alloy of copper (Cu) and tin (Sn). This question appeared previously in NDA 2011-I in a different form – the repeated testing confirms it is a core NDA concept. Concept Tested: Bronze – copper and tin alloy (repeated)

NDA 2021-I

Q. 4. Solder is an alloy of

(a) Cu and Sn.

(b) Fe and Zn.

(d) Ag and Zn.

Answer: (c) Pb and Sn.

Explanation: Solder is an alloy of lead (Pb) and tin (Sn), typically in 60:40 or 40:60 ratio. It has a low melting point and is used for joining metal parts in electronics and plumbing. Concept Tested: Composition of solder – lead and tin alloy

NDA 2011-I

Q. 5. Bronze is often used to make statues and medals whereas brass is used in making utensils, scientific apparatus and cartridges. Both brass and bronze are copper containing alloys, yet they differ in their chemical composition for additionally containing :

(a) Zinc in brass and tin in bronze.

(b) Chromium in brass and nickel in bronze.

(d) Iron in brass and nickel in bronze.

Answer: (a) Zinc in brass and tin in bronze.

Explanation: Brass = copper + zinc. Bronze = copper + tin. Both contain copper as the main metal, but brass adds zinc and bronze adds tin. This is a fundamental alloy composition fact. Concept Tested: Composition of brass and bronze – zinc and tin respectively

★ JOVIK Exam Insight: Brass vs bronze is a classic NDA alloy question. Brass = Cu + Zn. Bronze = Cu + Sn. Also repeated in NDA 2022-II. Learn: Br-ass = Zinc (Z), Br-onze = Tin (Sn).