Many transition metals form interstitial compounds. The characteristics of these interstitial compounds are
$(I)$ They have high melting points, higher than those of pure metals
$(II)$ They are very hard
$(III)$ They retain metallic conductivity
$(IV)$ They are chemically more reactive than the pure metals
$I,\,II,\,III$
$I, \,III$
$II,\, IV$
$IV$ only
Elements which generally exhibit multiple oxidation states and whose ions are usually coloured are
Amalgams are
Which one of the following statements shows the correct percentage of carbon in steel, pig iron and wrought iron
An oxide of copper which is red in colour has the formula
Stainless steel is an alloy of