Which of the following ions can reduce dilute acid to give hydrogen gas?
Which of the following ions can reduce dilute acid to give hydrogen gas?
$\mathrm{Ti}^{2+}, \mathrm{Cr}^{2+}$
$\mathrm{Mn}^{3+}, \mathrm{Ti}^{2+}$
$\mathrm{Mn}^{3+}, \mathrm{Cr}^{2+}$
$\mathrm{Co}^{3+}, \mathrm{Cr}^{2+}$
Solution
Many of transition metals are sufficiently electropositive to react with dilute acid in order to produce hydrogen gas. But those having lower standard reduction potential are not able to liberate $\mathrm{H}_2$ from dilute acid.