JEE Main 2021 · 24 February · morning · Single correct · +4 / −1
The major components in "Gun Metal” are :
- (a) Al, Cu, Mg and Mn
- (b) Cu, Ni and Fe
- (c) Cu, Sn and Zn
- (d) Cu, Zn and Ni
Answer and solution
Answer (c) Cu, Sn and Zn
Solution
Chemistry ma’am · 2 steps
Gun metal is a bronze: copper with tin, plus a little zinc. Match each option to its alloy.
- What gun metal is. Gun metal is a kind of bronze, about 88% Cu, 10% Sn and 2% Zn. The tin makes it hard and resistant to corrosion, and the zinc helps it flow when cast.
Option Metals Alloy it matches (a) Al, Cu, Mg, Mn Duralumin (mostly Al) (b) Cu, Ni, Fe Cupronickel type (mostly Cu and Ni) (c) Cu, Sn, Zn Gun metal (d) Cu, Zn, Ni German silver - So. Gun metal is copper, tin and zinc, so the answer is (c).
The idea to keep. Learn alloys in pairs with their base metal: Cu + Sn is bronze, Cu + Zn is brass, Cu + Sn + Zn is gun metal, Cu + Zn + Ni is German silver, and Al + Cu + Mg + Mn is duralumin.
Answer from the NTA final answer key. Solution by PrepWiser.