Question

Which of the following pair will not produce dihydrogen gas?

• A. $Cu+HCl\text{(dil.)}$
• B. $Fe+H_{2}S{O}_4$
• C. $Mg+\text{steam}$
• D. $Na+\text{alcohol}$

Answer 1

The correct option is A $Cu+HCl\text{(dil.)}$

From electrochemical series we can see that oxidation potential of Cu is less than H. Hence copper is less reactive toward oxidation than Hydrogen. All the other metal have higher oxidation potential than H hence they will reduce $H^{+}$ to Hydrogen gas.
$Cu+HCl\text{(dil.)}\to \text{No reaction}$