Question

Which of the following chemical equations is 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 of the correct option:

The correct option is B:

• A balanced chemical equation occurs when the number of the different atoms of elements on the reactants side is equal to that of the products side.
• $$\begin{gathered} 2{\mathrm{C}}_4{\mathrm{H}}_{10}+12{\mathrm{O}}_2\to 8{\mathrm{CO}}_2+10{\mathrm{H}}_2\mathrm{O} \\ \mathrm{C}=8\mathrm{C}=8 \\ \mathrm{H}=20\mathrm{H}=20 \\ \mathrm{O}=24\mathrm{O}=26 \end{gathered}$$
• As the number of atoms (oxygen) is not equal on both sides, the reaction is unbalanced.
• The correct balanced chemical equation for option B will be $2{\mathrm{C}}_4{\mathrm{H}}_{10}+13{\mathrm{O}}_2\to 8{\mathrm{CO}}_2+10{\mathrm{H}}_2\mathrm{O}$.

Explanation of the incorrect options:

• Options A, C, and D are balanced chemical equations as the number of atoms of all the molecules on both sides is equal.

Final Answer: Unbalanced chemical equation is $2{\mathrm{C}}_4{\mathrm{H}}_{10}+12{\mathrm{O}}_2\to 8{\mathrm{CO}}_2+10{\mathrm{H}}_2\mathrm{O}$.