Make up the reaction equation: Zn- ZnO- ZnCl2- Zn (OH) 2- ZnO, Ba- Bao- Ba (OH) 2- BaCO3- CO2- Na2CO3

A) 1. Zinc reacts with oxygen, we get – zinc oxide:

Zn + O2 → 2ZnO;

Zinc oxide reacts with hydrochloric acid, in the course of the presented reaction, zinc chloride and water are obtained:
ZnO + 2HCl → ZnCl2 + H2O;

In the process of interaction between zinc chloride and water, zinc hydroxide and hydrochloric acid are formed:
ZnCl2 + H2O → Zn (OH) 2 + 2HCl;

When zinc hydroxide is heated, we obtain zinc oxide and water:
Zn (OH) 2 → ZnO + H2O.

B) 1. Barium reacts with oxygen, we get – barium oxide:

2Ba + O2 → 2BaO;

When barium interacts with water, we get barium hydroxide and hydrogen is released:
Ba + 2H2O → Ba (OH) 2 + H2 ↑;

In the process of the exchange reaction of barium hydroxide with sodium carbonate, we obtain barium carbonate and water:
Ba (OH) 2 + H2CO3 → BaCO3 + H2O;

When barium carbonate is heated, we obtain barium oxide and carbon dioxide:
BaCO3 → BaO + CO2;

When carbon dioxide and sodium hydroxide interact, sodium carbonate and water are obtained:
CO2 + 2NaOH → Na2CO3 + H2O.