Which Of The Following Is A Correctly Balanced Equation

Which of the Following Is a Correctly Balanced Equation?

Balancing chemical equations is a fundamental skill in chemistry that ensures the law of conservation of mass is obeyed. When atoms are conserved, the number of atoms of each element on the reactant side must equal the number on the product side. This article walks through the logic behind balancing equations, demonstrates common pitfalls, and provides a step‑by‑step analysis of several sample reactions to determine which one is correctly balanced.

Introduction

In chemistry, an equation is more than a symbolic representation; it is a statement of a chemical transformation that must satisfy a strict rule: mass conservation. An unbalanced equation can lead to erroneous predictions about stoichiometry, energy changes, and product yields. So, chemists routinely check that every equation is balanced before using it in calculations or experimental design Small thing, real impact..

The question “Which of the following is a correctly balanced equation?On top of that, it tests not only memorization of reaction types but also the ability to apply algebraic reasoning to count atoms. On top of that, ” is a typical problem found in textbooks and exams. Below, we break down the balancing process, illustrate it with concrete examples, and explain how to spot the correct answer among a set of alternatives.

Honestly, this part trips people up more than it should.

The Balancing Process Explained

1. Write the Skeleton Equation

The skeleton equation lists the reactants and products without coefficients:

[ \text{A} + \text{B} \rightarrow \text{C} + \text{D} ]

2. Count Atoms of Each Element

Create a table that tallies the number of atoms for every element on both sides. To give you an idea, in the reaction between nitrogen and hydrogen to form ammonia:

[ \text{N}_2 + \text{H}_2 \rightarrow \text{NH}_3 ]

The counts are:

Element	Reactants	Products
N	2	1
H	2	3

3. Assign Coefficients

Introduce variables (e.Think about it: g. , (a, b, c, d)) as coefficients in front of each compound.

[ \begin{cases} 2a = c \ 2b = 3c \end{cases} ]

Solve for the smallest whole‑number coefficients that satisfy all equations.

4. Verify the Balance

After assigning coefficients, recalculate the atom counts to confirm equality on both sides. If any element is unbalanced, adjust coefficients and repeat Most people skip this — try not to..

Common Mistakes to Avoid

Mistake	Why It Happens	How to Fix It
Using fractions	Some students stop at fractional coefficients.	Systematically check every element, even those that appear balanced at first glance. Day to day,
Ignoring stoichiometric constraints	For reactions involving polyatomic ions, the overall charge may be overlooked.
Assuming the first solution is correct	Multiple sets of coefficients can satisfy the equations.
Neglecting to balance all elements	Focus may drift to the most obvious imbalance.	Verify charge balance in addition to atom counts.

Sample Reactions and Analysis

Below are four reactions commonly presented in coursework. We will determine which one is correctly balanced Most people skip this — try not to..

Reaction A
[ \text{C}_2\text{H}_6 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} ]
Reaction B
[ 2\text{Fe} + 3\text{O}_2 \rightarrow 2\text{Fe}_2\text{O}_3 ]
Reaction C
[ \text{NaOH} + \text{HCl} \rightarrow \text{NaCl} + \text{H}_2\text{O} ]
Reaction D
[ 4\text{H}_2\text{O} \rightarrow 2\text{H}_2 + 2\text{O}_2 ]

Let’s examine each one Easy to understand, harder to ignore..

Reaction A: Ethane Combustion

Skeleton:
[ \text{C}_2\text{H}_6 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} ]

Atom Counts (before coefficients):

Element	Reactants	Products
C	2	1
H	6	2
O	2	3

Assign Coefficients:
Let (a) be the coefficient for (\text{C}_2\text{H}_6), (b) for (\text{O}_2), (c) for (\text{CO}_2), (d) for (\text{H}_2\text{O}) Most people skip this — try not to..

Equations: [ \begin{aligned} 2a &= c \ 6a &= 2d \ 2b &= 3c + d \end{aligned} ]

Choosing (a = 1) gives (c = 2) and (d = 3). Plugging into the oxygen equation: [ 2b = 3(2) + 3 = 9 \Rightarrow b = 4.5 ] Since coefficients must be whole numbers, multiply all by 2: [ 2\text{C}_2\text{H}_6 + 9\text{O}_2 \rightarrow 4\text{CO}_2 + 6\text{H}_2\text{O} ]

Conclusion:
Reaction A as written is not balanced. The correct balanced form requires coefficients 2, 9, 4, and 6.

Reaction B: Iron Oxidation

Skeleton:
[ 2\text{Fe} + 3\text{O}_2 \rightarrow 2\text{Fe}_2\text{O}_3 ]

Check Atom Counts:

Element	Reactants	Products
Fe	(2 \times 1 = 2)	(2 \times 2 = 4)
O	(3 \times 2 = 6)	(2 \times 3 = 6)

Fe is unbalanced: 2 vs. 4. To balance Fe, change the coefficient of Fe on the reactant side to 4:

[ 4\text{Fe} + 3\text{O}_2 \rightarrow 2\text{Fe}_2\text{O}_3 ]

Now Fe: 4 = 4, O: 6 = 6. Reaction B, as given, is not balanced.

Reaction C: Neutralization

Skeleton:
[ \text{NaOH} + \text{HCl} \rightarrow \text{NaCl} + \text{H}_2\text{O} ]

Atom Counts:

Element	Reactants	Products
Na	1	1
O	1	1
H	1 + 1 = 2	2
Cl	1	1

All elements are balanced. Think about it: coefficients are all 1. Reaction C is correctly balanced.

Reaction D: Electrolysis of Water

Skeleton:
[ 4\text{H}_2\text{O} \rightarrow 2\text{H}_2 + 2\text{O}_2 ]

Atom Counts:

Element	Reactants	Products
H	(4 \times 2 = 8)	(2 \times 2 = 4) + (0 = 4)
O	(4 \times 1 = 4)	(2 \times 2 = 4)

Hydrogen is unbalanced (8 vs. 4). To correct, double the coefficient of (\text{H}_2):

[ 4\text{H}_2\text{O} \rightarrow 4\text{H}_2 + 2\text{O}_2 ]

Now H: 8 = 8, O: 4 = 4. Reaction D, as written, is not balanced Simple as that..

Which Equation Is Correctly Balanced?

From the analysis above, Reaction C (the neutralization of sodium hydroxide with hydrochloric acid) is the only one that is already balanced with integer coefficients. The other reactions require adjustment of coefficients to satisfy mass conservation Simple, but easy to overlook..

Frequently Asked Questions

1. Why do some balanced equations use fractional coefficients?

Fractional coefficients can arise when the simplest set of integers is not immediately apparent. Multiplying all coefficients by the denominator of the fractions yields an equivalent balanced equation with whole numbers, which is the preferred form.

2. Do I need to balance charges in redox reactions?

Yes. In redox reactions, balancing electrons (or charges) is essential. While the atom count ensures mass conservation, charge balance ensures electrical neutrality, especially in aqueous solutions.

3. Can a balanced equation be wrong if the reaction doesn't actually occur?

A mathematically balanced equation may represent a possible reaction, but it might be kinetically unfavorable or thermodynamically impossible. Chemistry balances constraints of both mass and energy.

4. How do I handle polyatomic ions that stay together?

Treat the polyatomic ion as a single unit when counting atoms. Take this: in (\text{CaSO}_4), count one calcium, one sulfur, and four oxygens as one compound.

5. Is there software that can balance equations automatically?

Yes, many computational tools and calculators can balance equations. That said, understanding the underlying principles is crucial for interpreting results and troubleshooting errors.

Conclusion

Balancing chemical equations is a disciplined exercise that reinforces the conservation of mass principle. Practically speaking, by systematically counting atoms, assigning coefficients, and verifying balance, chemists can confidently write equations that reflect real chemical processes. Among the sample reactions examined, Reaction C stands out as the correctly balanced equation. Mastery of this skill not only prepares students for academic assessments but also equips them with a foundational tool for research, industry, and everyday problem-solving in chemistry That's the part that actually makes a difference..