Answer:
A.
Explanation:
zinc and hydrochloric acid reacts to form zinc chloride and hydrogen.
hope it helps. :)
D. All of the above are indicators of chemical change
<u>Answer:</u> The true statement is iron can reduce
to gold metal
<u>Explanation:</u>
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.
![A+BC\rightarrow AC+B](https://tex.z-dn.net/?f=A%2BBC%5Crightarrow%20AC%2BB)
Metal A is more reactive than metal B.
We are given:
Iron can reduce copper, silver can reduce gold, sodium can reduce iron and copper can reduce silver metal.
The increasing order of reactivity thus follows:
![Au](https://tex.z-dn.net/?f=Au%3CAg%3CCu%3CFe%3CNa)
where, sodium is most reactive and gold is least reactive
For the given options:
<u>Option 1:</u> Copper cannot easily reduce sodium ion to sodium metal because it is less reactive.
![Cu(s)+Na^+(aq.)\rightarrow \text{ No reaction}](https://tex.z-dn.net/?f=Cu%28s%29%2BNa%5E%2B%28aq.%29%5Crightarrow%20%5Ctext%7B%20No%20reaction%7D)
<u>Option 2:</u> Iron cant easily reduce gold ion to gold metal because it is more reactive.
![Fe(s)+3Au^+(aq.)\rightarrow Fe^{3+}(aq.)+3Au(s)](https://tex.z-dn.net/?f=Fe%28s%29%2B3Au%5E%2B%28aq.%29%5Crightarrow%20Fe%5E%7B3%2B%7D%28aq.%29%2B3Au%28s%29)
<u>Option 3:</u> Silver cannot easily reduce iron ion to iron metal because it is less reactive.
![Ag(s)+Fe^{3+}(aq.)\rightarrow \text{ No reaction}](https://tex.z-dn.net/?f=Ag%28s%29%2BFe%5E%7B3%2B%7D%28aq.%29%5Crightarrow%20%5Ctext%7B%20No%20reaction%7D)
Hence, the true statement is iron can reduce
to gold metal
Answer:
mol times or devided by molar volume