Which of the following statements is correct concerning the reaction 2a + b → 2c + 2d?

• A. The reaction is not balanced because there are more products than reactants.
• B. The reaction is balanced because the number of atoms of each element is the same on both sides.
• C. The reaction is not balanced because the coefficients of the reactants do not match those of the products.
• D. The reaction is balanced only if a, b, c, and d represent the same element.

Answer: (B)

Verified step by step guidance

1. Identify the chemical equation given: \$2a + b \rightarrow 2c + 2d$.
2. Understand that balancing a chemical equation means the number of atoms of each element must be the same on both sides of the reaction.
3. Note that the letters a, b, c, and d represent chemical species (which could be elements or compounds), and the coefficients (numbers in front) indicate the relative amounts of each species.
4. Check if the total number of atoms for each element is equal on both sides by considering the coefficients and the composition of each species. Since the problem uses generic symbols, assume each letter represents a distinct species.
5. Conclude that the equation is balanced if the total atoms of each element on the reactant side equal those on the product side, which is true here because the coefficients balance the species as given.