Question

consider the reaction 2a + b → c. the diagram shown below represents the beginning of the reaction. which reactant, a or b, is the limiting reactant? impossible to determine without more information a b

Explanation:

Step1: Analyze the stoichiometry of the reaction

The reaction is \(2A + B
ightarrow C\). This means that for every \(1\) molecule of \(B\), \(2\) molecules of \(A\) are required.

Step2: Count the number of \(A\) and \(B\) molecules

Let's assume the number of \(A\) molecules \(n(A)= 10\) and the number of \(B\) molecules \(n(B) = 6\). According to the stoichiometry \(n(A)_{required}=2\times n(B)\). If we use all \(B\) molecules (\(n(B) = 6\)), we need \(n(A)_{required}=2\times6 = 12\) \(A\) molecules. But we have only \(10\) \(A\) molecules.
Another way: If we use all \(A\) molecules (\(n(A)=10\)), the number of \(B\) molecules required \(n(B)_{required}=\frac{n(A)}{2}=\frac{10}{2}=5\). Since we have \(6\) \(B\) molecules (more than required when \(A\) is fully - consumed), \(A\) will be used up first.

Answer:

A. A