Chapter 20, Problem 2RAT

To determine

The correct option for the statement “Which equation is balanced”.

Answer to Problem 2RAT

The correct option for the statement “Which equation is balanced” is option (a).

Explanation of Solution

Any reaction containing identical number of reacting atoms as well as produced atoms is referred as balanced equation.

In (a) the chemical equation given is,

$\text{Mg}\left(\text{s}\right)+\text{2HCl}\left(\text{aq}\right)\to {\text{MgCl}}_2\left(\text{aq}\right)+{\text{H}}_2\left(\text{g}\right)$ ,

There is one magnesium atom in the reactant side and one magnesium atom on the product side, so the magnesium atom is balanced in the above equation.

Similarly, there are two chlorine atoms in the reactant side and two chlorine atoms on the product side, so the chlorine atoms are balanced in the above equation.

Also, there are two hydrogen atoms in the reactant side and two hydrogen atoms on the product side, so the hydrogen atoms are balanced in the above equation.

Thus, the reaction is balanced.

In (b) the chemical equation is given,

$\text{3Al}\left(\text{s}\right)+{\text{2Br}}_2\left(\text{l}\right)\to {\text{Al}}_2{\text{Br}}_3\left(\text{s}\right)$ ,

There are three aluminum atoms in the reactant side and two aluminum atoms on the product side, so the aluminum atoms are not balanced in the above equation.

Also, there are four bromine atoms in the reactant side and three bromine atoms on the product side, so the bromine atoms are not balanced in the above equation.

Thus, the reaction is not balanced.

In (c) the chemical equation given is,

$\text{2HgO}\left(\text{s}\right)\to 2\text{Hg}\left(\text{l}\right)+{\text{2O}}_2\left(\text{g}\right)$ ,There are two mercury atoms in the reactant side and two mercury atoms on the product side, so the mercury atoms are balanced in the above equation.

And there are two oxygen atoms in the reactant side and four oxygen atoms on the product side, so the oxygen atoms are not balanced in the above equation.

Thus, the reaction is not balanced.

Conclusion:

Therefore, the correct option is option (a).