Chemistry of Metals and Alloys

Argon is used in welding metals.

This is the correct option as silver is the best conductor of heat but as it is expensive, it is not used extensively.

This option is correct because nichrome wire, stainless steel and inconel all contain chromium in their alloy composition.

Correct answer. The metal ions not having unpaired electrons (n−1)d⁰ or having completely filled d orbital (n−1)d¹⁰ do not absorb radiations in visible region, since d-d transitions are not possible. Hence, they are colourless ions. Among the given ions, Ag⁺ (4d¹⁰), V⁵⁺ (3d⁰), Cd²⁺ (4d¹⁰) are colourless.

Bi (III) salts are used in the treatment of gastric ulcers.

Gunmetal is a type of bronze – an alloy of copper (88%), tin (10%), and zinc (2%).

The substances which are strongly attracted by magnetic field and show permanent magnetism even in the absence of magnetic field are ferromagnetic. For example: Fe, Co, Ni etc.

Copper was the first metal discovered and used by humans, marking the beginning of the Chalcolithic period or Copper Age. It was relatively easy to extract and shape compared to other metals.

Red phosphorus is used in the manufacture of safety matches because it is less reactive than white phosphorus and can be ignited by friction on the striking surface.

Carbon is a fundamental element of life and is cycled through biological processes, not accumulated as a persistent toxic pollutant in the way heavy metals or DDT are.

The Indus Valley Civilization was a Bronze Age civilization. While they used copper, bronze, gold, and silver, there is no archaeological evidence that they knew about or used iron.

Pure gold is too soft for making durable ornaments. Copper is commonly added as an alloying agent to increase the hardness and strength of the gold.

Gold is the most malleable and ductile metal. It can be hammered into extremely thin sheets (gold leaf) without breaking, which is a key property for its use in jewelry and electronics.

Pure gold is defined as 24-carat gold. Lower carat values indicate that the gold has been alloyed with other metals to increase its strength.