Task: Question Answering
Input (English): Question: If the normal reduction potential of the pair Zn2 + / Zn is -0.76 V: 
 Options:  <1> Aqueous solutions of Zn2 + at pH = 0 release oxygen. <2> Putting metallic Zn in aqueous solution at pH = 0 releases oxygen. <3> Aqueous solutions of Zn2 + at pH = 0 give off hydrogen. <4> By putting metallic Zn in aqueous solution at pH = 0, hydrogen is evolved. <5> Zn2 + dismutates in aqueous solution at pH = 0.
Output (English): 4