Question

Rafa places some copper into a solution of sodium chloride. No reaction takes place. Using the displacement theory, explain why no reaction took place?

Answer 1

Na more reactive than Cu

Further explanation

Given

Copper in a solution of NaCl

Required

The displacement theory

Solution

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

Not all of these reactions can occur. We can use the activity series, which is a list of elements that can replace other elements below / to the right of them in a single replacement reaction.

The voltaic series:  

Li-K-Ba-Ca-Na-Mg-Al-Mn- (H2O) -Zn-Cr-Fe²⁺-Cd-Co-Ni-Sn-Pb- (H) -Cu-Hg-Fe³⁺-Ag-Pt-Au  

The electrode which is easier to reduce than the hydrogen (H2) electrode has a positive sign (E red= +) and is located to the right of the voltaic series (right of H)  

The electrode which is easier to oxidize than the hydrogen (H2) electrode and is difficult to experience reduction has a negative sign (E red= -) and is located to the left of the voltaic series (left of H)

Reaction

Cu + NaCl≠

The existing copper element can not replace the sodium element, which is on the left side so the reaction will not occur.

But if it is reversed, then a reaction can occur

2 Na + CuCl2 → Cu + 2 NaCl