Which of the following metals does not react with water to produce hydrogen?

Step 1: Analyze the question We need the metal that does not react with water to give hydrogen gas. This is a question about the reactivity series.

Step 2: The concept In the reactivity series, the order from most to least reactive is:

K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Ag > Au

• Metals above hydrogen can displace it from water or acid, in some form. Very reactive ones (K, Na, Ca) react with cold water. Mg reacts with hot water or steam. Zn and Fe react with steam.
• Metals below hydrogen (Cu, Ag, Au) do not displace hydrogen from water at all.

Step 3: Check each option

• A. Copper: It is below hydrogen in the series, so it does not react with water or steam. ✔
• B. Potassium: It reacts violently with cold water: 2K + 2H₂O → 2KOH + H₂
• C. Sodium: It reacts vigorously with cold water: 2Na + 2H₂O → 2NaOH + H₂
• D. Zinc: It does not react with cold water, but it reacts with steam: Zn + H₂O(g) → ZnO + H₂. So it does produce hydrogen under the right conditions.

Step 4: Answer Copper is the metal that does not react with water or steam to produce hydrogen.

Tip: Remember the reactivity series with the phrase "Please Stop Calling Me A Careless Zebra, Instead Try Learning How Copper Saves Gold" (K, Na, Ca, Mg, Al, C, Zn, Fe, Sn, Pb, H, Cu, Ag, Au). Anything below H (Cu, Ag, Au) will not give hydrogen with water or dilute acids. In "which does not react" questions, pick the metal lowest in the series.