Question

question 4
what signifies a reversible chemical reaction?
a single arrow between reactants and products.
a double arrow between reactants and products.
the presence of a catalyst.
the absence of any change in temperature.

Explanation:

In chemical reactions, a double - arrow ($
ightleftharpoons$) between reactants and products indicates that the reaction can proceed in both the forward and reverse directions, which is the characteristic of a reversible reaction. A single arrow means a non - reversible reaction. A catalyst only affects the rate of a reaction and not whether it is reversible or not. The absence of temperature change is not a sign of a reversible reaction.

Answer:

B. A double arrow between reactants and products.