Question

When Calcium (Ca) is mixed with Hydrochloric acid (HCI), a single-displacement reaction occurs. What will be the product or products?
a) CaCI2
b) CaCI2+H2
c) Ca+HCI
d) CI and H

Answer 1

Answer: The correct answer is Option b.

Explanation:

Single displacement reaction is defined as the reaction in which more reactive element displaces a less reactive element from its chemical reaction.

The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.

When calcium metal reacts with hydrochloric acid, it leads to the formation of a salt known as calcium chloride and also releases hydrogen gas.

The chemical equation for the above reaction follows:

$Ca(s)+2HCl(aq.)\rightarrow CaCl_2(s)+H_2(g)$

Hence, the correct answer is Option b.

Answer 2

The correct answer is b. In a single-displacement reaction one element replaces another one, and because of BrINClHOF we know that hydrogen must have a 2 with it when it's by itself. Since calcium is +2 and chlorine is -1, you have to cross the charges. So it would be CaCl2.