Question

Q.Balance the following chemical equations.

i) Na+H2O--> NaOH+H2
ii) AI+O2--> AI2O3
iii) Mg+H2O--> MgO+H2
iv)HCI+NaOH-->NaCI+H2O
v)CaCO3-->CaO+CO2​

Answer 1

1. Na + 2H2O ------→ 2NaOH + H2

2. 4Al + 3O2 -------→ 2Al2O3

3. Mg + H2O -------→ MgO + H2

4. 2HCl + NaOH -------→ 2NACl +2H2O

5. CaCO3 --------→ CaO + CO2 .

Answer 2

i) Na + H2O → NaOH + H2

$\sf{2Na+2H_2O \rightarrow 2NaOH+H_2}$

It is a Displacement Reaction because in this reaction one element displace an other element in a compound.

ii) Al + O2 → Al2O3

$\sf{4Al+3O_2 \rightarrow 2Al2O3}$

Given reaction is Combination Reaction. As two or more elements combination to form a single compound.

iii) Mg + H2O → MgO + H2

$\sf{Mg+H_2O \rightarrow MgO+H_2}$

(This reaction is already balanced)

In this reaction Magnesium is more reaction than Hydrogen. So, it will displace Hydrogen from it's solution. Such type of reaction is known as Displacement Reaction.

iv) HCl + NaOH → NaCl + H2O

$\sf{HCl+NaOH \rightarrow NaCl+H_2O}$

(Reaction is already balanced)

It is a Neutralization Reaction, as acid and base react with each other to form salt and water.

v) CaCO3 → CaO + CO2

$\sf{CaCo_3 \rightarrow CaO + CO_2}$

(Reaction is already balanced)

Calcium carbonate decomposes by heat and produces Carbon dioxide gas and Calcium oxide. The given reaction is Thermal Decomposition Reaction. Also, it is Endothermic Reaction.