Pair of ions which gives blue colour in aqueous state :
$V^{+4},\,Ni^{+2},\, Ti^{+3}, \,Co^{+2}, \,Fe^{+3}, \,Cu^{+2}$
$V^{+4},\, Cu^{+2}$
$Co^{+2}, \,Ni^{+2}$
$Fe^{+3},\, Ti^{+3}$
$Cr^{+3}, \,Zn^{+2}$
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.
Among the following, the compound that is both are diamagnetic and coloured is
Why does copper not replace hydrogen from acids?
Which ion has maximum magnetic moment
The correct formula of permanganic acid is