You notice that every time you place butter on your stack of freshly made pancakes, the butter melts. According to the law of conservation of energy, heat lost by the pancake

Heat lost by the pancake = Heat gained by butter

Explanation:

Because energy is always conserved, this process involves the loss of energy by one substance which is gained by another.

The pancakes were freshly made, so they are hot; having the required energy to melt the butter placed on them. The butter absorbs heat from the pancakes which is equal to or greater than its melting point. Thus, the butter melts due to the heat absorbed.

Therefore,

Heat lost by the pancakes = Heat gained by butter

Water is polar molecule, ionic compound dissolves in it as like dissolves like.

there is ionic interaction between a salt and water

Sugar has hydroxyl group in it. These hydroxyl group are able to form hydrogen bond with water molecule.

[Hydrogen bond : the interaction between a hydrogen, bonded with a highly electro-negative element (F,O,N) and other highly electro-negative element (F,O,N)]

Thus due to hydrogen bond sugar is soluble in water.

Explanation:The water molecules, , are polar, with positive partial charges on the hydrogen and a negative partial charge on the oxygen. This makes it possible to interact with ionic compounds such as salt (NaCl). This interaction occurs through the partially positive and negative ends of the water, so that the positive charges attract the negative ones. The NaCl salt in water dissociates (separates) into  and  ions. ions are surrounded by negative partial charges of water oxygen, while  ions are surrounded by hydrogen ends with positive partial charge. In this way the salt is dissolved in water.

Sugar is a molecular compound formed by covalent bonds. In a polar covalent bond, electrons are shared unevenly. This creates a slightly negatively charged end and a slightly positively charged end. This is what happens with sugar. These extremes are those that interact with the positive and negative extremes of water, mentioned previously. Then it is possible to say that sugar dissolves in water because both substances are polar substances.

In short, water dissolves most of the substances that are polar or ionic, as in the case of sugar and salt.