i-adjective
low-melting; easily thawed
Describes substances that melt or thaw at a relatively low temperature or with little heat.
このチョコレートは溶けやすいから、冷蔵庫に入れておいて。
This chocolate melts easily, so keep it in the fridge.
春先の雪は溶けやすい。
Snow in early spring thaws easily.
i-adjective
Used for substances that dissolve readily in a liquid, such as sugar or salt in water.
砂糖は水に溶けやすい。
Sugar is soluble in water.
溶ける is the base verb meaning 'to melt' or 'to dissolve'; 溶けやすい is the adjective form meaning 'easy to melt/dissolve'.
解ける means 'to come untied' or 'to be solved', not related to melting.
Compound of 溶け (continuative form of 溶ける 'to melt/dissolve') + やすい ('easy to').