Below is the equation for the formation of hydrofluoric acid:
H2(g) + F2(g) ←→ 2 HF(g) + 546kJ
What type of reaction does this equation represent?

The answer to your question is Synthesis and Endothermic

Explanation:

Balanced chemical reaction

               H₂  +  F₂   ⇒   2HF  + 546 kJ

Chemical reactions can be classified in different ways, so I suggest two names of this reaction.

1.- This is a synthesis reaction because two different reactants form a new  compound.

2.- This is an endothermic reaction because it was needed  to supply 546 kJ of energy so that the reaction proceeds.

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.