Question

imagine you are in a laboratory. you are explor the following reaction: $a + b \to c$ when the product c is created, bubbles form. when 10ml of a is added to 10ml of b, the reaction takes twenty seconds. your teacher give you three unknown substances (x, y, and z), one of which is a catalyst for the reaction. design an experiment to test substances x, y, an z to determine which one is a catalyst for the reaction.

Explanation:

Step1: Set up control experiment

First, conduct the reaction \(A + B
ightarrow C\) without adding any of \(X\), \(Y\), or \(Z\). Measure the time \(t_0 = 20\) s (given in the problem). This is the baseline reaction time.

Step2: Test substance \(X\)

Add a small, consistent amount (e.g., same mass or volume, say \(m\)) of substance \(X\) to the reaction mixture of \(10\) mL of \(A\) and \(10\) mL of \(B\). Measure the time \(t_X\) it takes for the bubbles (indicating the formation of \(C\)) to form completely.

Step3: Test substance \(Y\)

Repeat the process in Step 2, but substitute \(X\) with substance \(Y\). Measure the time \(t_Y\).

Step4: Test substance \(Z\)

Repeat the process in Step 2, but substitute \(X\) with substance \(Z\). Measure the time \(t_Z\).

Step5: Analyze results

A catalyst speeds up a chemical reaction without being consumed in the reaction. So, compare \(t_X\), \(t_Y\), \(t_Z\) with \(t_0\). The substance (either \(X\), \(Y\), or \(Z\)) for which the reaction time \(t_i\) (\(i = X,Y,Z\)) is significantly less than \(t_0\) (while keeping the amounts of \(A\) and \(B\) constant) is the catalyst.

Answer:

Set up four reaction - mixtures: one with just \(A\) and \(B\) (control), and three others with \(A + B+X\), \(A + B + Y\), \(A + B+Z\). Measure the reaction times. The substance that causes the reaction \(A + B
ightarrow C\) to occur in a time significantly less than the control (20 s) is the catalyst.