Question

According to Reference Table J, which of these metals will react mostreadily with 1.0 M HCl to produce H2(g)?(1) Ca (3) Mg(2) K (4) Zn

Answer 1

Answer: The correct answer is Option 2.

Explanation:

The reaction between a metal and HCl is a type of single displacement reaction.

Single replacement reactions are defined as the reactions in which more reactive metal replaces less reactive metal from its chemical equation. The reactivity is determined from the series called reactivity series. The metal lying above in the series is more reactive than the metal lying below in the series.

General equation for these types of reactions is:

$AB+C\rightarrow CB+A$

From the series attached below, the most reactive metal is Potassium (K).

Increasing order of the reactivity of metals are:

$Zn$

Hence, the correct answer is Option 2.

Answer 2

Reference table J?

In general though reactions happen when one element wants to replace another element in another molecule/compound. So in this case you are essentially looking for the most reactive metal of the 4 choices. Elements become more reactive as you go down the periodic table, and metals become more reactive as you move left along the period, meaning Alkali metals are the most reactive metals, and Francium is the most reactive metal. 

Based on this knowledge we can assume that Potassium is the most reactive of the choices and thus most readily reacts with HCl to produce H2 gas. And if you want prood check out this video!

https://www.youtube.com/watch?v=53T5WZHQ_Ck