Question map
Which one of the following elements will not react with dilute HC1 to produce H2 ?
Explanation
The reaction between a metal and dilute hydrochloric acid (HCl) to produce hydrogen gas (H2) depends on the metal's position in the reactivity series relative to hydrogen. Metals located above hydrogen in the series can displace it from dilute acids to form a salt and hydrogen gas. Magnesium (Mg), Aluminium (Al), and Iron (Fe) are all more reactive than hydrogen and thus react with dilute HCl to evolve hydrogen bubbles [1]. Specifically, magnesium reacts the most vigorously, followed by aluminium and iron [1]. Conversely, metals situated below hydrogen in the reactivity series, such as Mercury (Hg), Copper (Cu), Silver (Ag), and Gold (Au), are unreactive with dilute HCl and do not produce hydrogen gas [1]. Therefore, Mercury (Hg) is the element among the options that will not react with dilute HCl to produce H2.
Sources
- [1] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > Activity 3.11 > p. 44