# Platinum, palladium, iridium etc., are called noble metals because

$\begin{array}{1 1}(a)\;\text{Alfred Noble discovered them}\\(b)\;\text{They are shining lustrous and pleasing to look at}\\(c)\;\text{They are inert towards many common reagents}\\(d)\;\text{They are found in active state}\end{array}$

Answer: They are inert towards many common reagents.
The noble metals are metals that are resistant to corrosion and oxidation in moist air, unlike most base metals. They tend to be precious, often due to their rarity in the Earth's crust. The noble metals are most commonly considered to be ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, and gold
edited Jul 30, 2014