A pink coloured salt turns blue on heating. The presence of which cation is most likely ?
$Co^{2+}$
$Cu^{2+}$
$Zn^{2+}$
$Fe^{2+}$
For the following Assertion and Reason, the correct option is
Assertion : For hydrogenation reactions, the catalytic activity increases from Group $5$ to Group $11$ metals with maximum activity shown by Group $7-9$ elements.
Reason : The reactants are most strongly adsorbed on group $7-9 $ elements.
Which of the following ions is coloured
Which element is alloyed with copper to form bronze
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
The catalytic activity of the transition metals and their compounds is ascribed to their