Question

Which of the following chemical equations in an unbalanced one?

• A. $2{NaHCO}_3\to {Na}_2{CO}_3+H_{2}O+{CO}_2$
• B. $2C_4{H}_{10}+12O_2\to 8{CO}_2+10H_{2}O$
• C. $2Al+6H_{2}O\to 2Al{\left(OH\right)}_3+3H_2$
• D. $4{NH}_3+5O_2\to 4NO+6H_{2}O$

Answer 1

The correct option is B

$2{\mathrm{C}}_4{\mathrm{H}}_{10}+12{\mathrm{O}}_2\to 8{\mathrm{CO}}_2+10{\mathrm{H}}_2\mathrm{O}$

Explanation for correct option:

B:

• A reaction is said to be balanced if the total number of atoms of each element is equal on both sides of the reaction, that is the reactant side as well as the product side.
• The given reaction is:

$2{\mathrm{C}}_4{\mathrm{H}}_{10}+12{\mathrm{O}}_2\to 8{\mathrm{CO}}_2+10{\mathrm{H}}_2\mathrm{O}$

• The table to represent the number of atoms of each element involved is:

Element	Reactant Side	Product Side
Carbon(C)	8	8
Hydrogen (H)	20	20
Oxygen (O)	24	26

Due to the presence of unequal number of oxygen atoms (O) on both sides of the equation, the given equation is said to be unbalanced.

Explanation for incorrect options:

A: The given reaction is:

$2{\mathrm{NaHCO}}_3\to {\mathrm{Na}}_2{\mathrm{CO}}_3+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$

The table to represent the number of atoms of each element involved is:

Element	Reactant Side	Product Side
Sodium (Na)	2	2
Carbon (C)	2	2
Hydrogen (H)	2	2
Oxygen (O)	6	6

Due to the presence of equal number of atoms of each element on both sides, the given equation is said to be balanced

C: The given reaction is:

$2\mathrm{Al}+6{\mathrm{H}}_2\mathrm{O}\to 2\mathrm{Al}{\left(\mathrm{OH}\right)}_3+3{\mathrm{H}}_2$

The table to represent the number of atoms of each element involved is:

Element	Reactant Side	Product Side
Aluminum (Al)	2	2
Hydrogen (H)	12	12
Oxygen (O)	6	6

Due to the presence of equal number of atoms of each element on both sides, the given equation is said to be balanced

D: The given reaction is:

$4{\mathrm{NH}}_3+5{\mathrm{O}}_2\to 4\mathrm{NO}+6{\mathrm{H}}_2\mathrm{O}$

The table to represent the number of atoms of each element involved is:

Element	Reactant Side	Product Side
Nitrogen (N)	4	4
Hydrogen (H)	12	12
Oxygen (O)	10	10

Due to the presence of equal number of atoms of each element on both sides, the given equation is said to be balanced.

Hence, option B is correct.