Which of the following statements is not correct?

Copper liberates hydrogen from acids

 $T{i}^{2+}$ and  $C{r}^{2+}$ are reducing agents in aqueous solution

In its higher oxidation states, manganese forms stable compounds with oxygen and fluorine

$M{n}^{3+}$and $C{o}^{3+}$ are oxidising agents in aqueous solution