General Chemistry
Ni(s) + H+(aq) → Ni+(aq) + H2(g)
Ni(s) + 2 H+(aq) → Ni2+(aq) + 2 H(g)
Ni(s) + 2 H+(aq) → Ni2+(aq) + H2(g)
Ni(s) + 2 H+(aq) → Ni2–(aq) + H2(g)