Question

question 4
20 pts
the reaction of decomposition of hydrogen peroxide h₂o₂ in a water solution is:
$ce{2 h_{2}o_{2}(aq) ->fe(no_{3})_{3} o_{2}(g) + 2 h_{2}o(l) + heat}$ ($delta h < 0$)
which one of the following statements does not describe or does not apply to the reaction?

• iron(iii) nitrate is used to speed up the reaction. without it the reaction would go slower.
• as the reaction is occurring, the reaction mixture is cooling down by itself and the flask feels cold to the touch.
• a gas is produced during the reaction and bubbles are observed in the solution.
• the reaction will occur faster when a warm h₂o₂ solution is used instead of a cold h₂o₂ solution.

Explanation:

1. Analyze the reaction: The reaction is \( 2H_2O_2(aq)\xrightarrow{Fe(NO_3)_3}O_2(g) + 2H_2O(l)+heat \) (\(\Delta H<0\)), so it's an exothermic reaction (releases heat).
2. Evaluate each option:

• Option 1: \( Fe(NO_3)_3 \) is a catalyst (speeds up reaction). Without it, reaction is slower. This applies.
• Option 2: For an exothermic reaction, the system (reaction mixture) releases heat, so the surroundings (flask) should feel warm, not cold. So this statement does not apply.
• Option 3: The product \( O_2(g) \) is a gas, so bubbles (from \( O_2 \)) are observed. This applies.
• Option 4: Increasing temperature (using warm solution) increases reaction rate. So reaction is faster with warm \( H_2O_2 \). This applies.

Answer:

The option that does not apply is: As the reaction is occurring, the reaction mixture is cooling down by itself and the flask feels cold to the touch.