$A$ hard and resistant metal alloy generally used in the tip of the nib of a fountain pen is

The false statement about iron $(III)$ hydroxide is that

$CoO \cdot Al_2O_3$ is called

Manganese steel is used for making railway tracks because

Highest fluoride and highest oxide of $Mn$ are respectively

$A$ metal $M$ which is not affected by strong acids like conc. $HNO_3$,conc. $H_2SO_4$ and conc. solutions of alkalies like $NaOH$,$KOH$ forms $MCl_3$,which finds use for toning in photography. The metal $M$ is: