<u>Answer:</u> The correct answer is Option d.
<u>Explanation:</u>
According to Lewis acid-base concept:
The substance which is donating electron pair is considered as Lewis base and the substance which is accepting electron pair is considered as Lewis acid.
For the given chemical reaction:

is accepting electron pair and is getting converted to
. Thus, it is considered as Lewis acid.
present in CuO is a Lewis base because it is donating electron pair.
Thus, the correct answer is Option d.
Answer:

Explanation:
The contact between the sheet of gold and the sheet of iron allows a heat transfer until thermal equilibrium is done, which means that both sheets have the same temperature:






The final temperature is:

The others are wrong it's B. Condensation