$Ti^{2+}$ $-0.37$
$V^{2+}$ $-0.26$
$Cr^{2+}$ $-0.41$
$Mn^{2+}$ $+1.57$
Negative value of $E^o$ means these metals librate hydrogen from dilute acid.
$({M^{2 + }}\, + \,2{H^ + }\, - \,{e^ - }\, \to \,{M^{3 + }}\, + \,{H_2})$
$Pt | H_2\,(g) | H^{+}_{(aq)} (10^{-8}\, M) | | H^{+}_{(aq)} (0.001\,M) | H_2\,(g) | Pt$
$Cu ( s )+ Sn ^{2+}( aq ) \rightarrow Cu ^{2+}( aq )+ Sn ( s )$
$\left( E _{ Sn ^{2+} \mid Sn }^{0}=-0.16\, V , E _{ Cu ^{2+} \mid Cu }^{0}=0.34\, V \right.$ Take $F=96500\, C\, mol ^{-1}$ )