Zinc metal reacts with hydrochloric acid to produce hydrogen gas. what best describes this reaction?
a. A single replacement reaction takes place because zinc is more reactive and hydrogen
b. A single replacement reaction takes place because zinc is more reactive than chlorine
c. A double replacement reaction takes place because zinc is less reactive than hydrogen
d. A double replacement reaction takes place because zinc is less reactive than chlorine

a. A single replacement reaction takes place because zinc is more reactive and hydrogen

In voltaic series  

Li-K-Ba-Ca-Na-Mg-Al-Mn- (H2O) -Zn-Cr-Fe-Cd-Co-Ni-Sn-Pb- (H) -Cu-Hg-Ag-Pt-Au  

The more to the left, the metal is more reactive (easily release electrons) and the stronger reducing agent  

The more to the right, the metal is less reactive (harder to release electrons) and the stronger oxidizing agent

So that the element located on the left can push the element on the right in the redox reaction

Reaction

Zn+2HCl ⇒ ZnCl₂ + H₂

If we look at this reaction, the elements that play a role are those that undergo a redox reaction

Oxidation : Zn⇒Zn²⁺ + 2e

Reduction : 2H⁺ + 2e ⇒H₂

So Zn (located on the left) can push H (the element on the right) in the redox reaction ⇒ Zn more reactive

A single replacement reaction is a chemical reaction in which one element replaces the other elements of a compound to produce new elements and compounds

A+BC⇒AC+B

So the above reaction involves the elements Zn and H which undergo a redox reaction and are included in a single replacement

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

c.

explanation: