Written by Prerak Juthani (PEACE Advisor)
a) The sugar decomposition is non-spontaneous.
b) The sugar decomposition occurs, but it needs a catalyst, and since there is no catalyst, the process is not spontaneous.
c) The rate of decomposition is too slow to observe in the time span of a human life.
d) Mitochondria is the powerhouse of the cell.
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The one thing that is important to remember here is that kinetics is completely INDEPENDENT of thermodynamics. In other words, just because something is favorable/spontaneous (delta G< 0) does not mean that it is kinetically favorable (that it will proceed quickly). That is exactly the situation we have here; the sugar decomposition reaction may be spontaneous, but it does not occur because the rate is extremely slow to observe in real life.
However, if you did want to observe this decomposition taking place, you can add in a catalyst, which is going to lower an activation energy and make the reaction go. This is similar to what B says, but it is not the same. Answer choice B states that a catalyst makes the process spontaneous (and lack of a catalyst make it non-spontaneous); this is INCORRECT. The catalyst has NO influence on the thermodynamics; instead, it actually just speeds up the reaction by decreasing the activation energy. This makes answer choice B wrong.
And lastly, answer choice A is incorrect because a negative delta G correlates to a spontaneous process.