What does the symbol (–hfus) indicate in a phase change?

(D) Liquid is being formed.

Explanation:

The enthalpy of fusion of a substance (–Hfus) is the change in its enthalpy when the substance changes its state from a solid to a liquid. It happens when heat is supplied to some quantity of substance which is originally in solid state & it turns into liquid.

Example- melting of ice.

To melt ice energy is required. Approximately, 333 kJ of energy is needed to heat 1 kg ice to convert into liquid.

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.