Why does water stop boiling when sugar is added to it when it is boiling ?

The boiling point of water depends on the pressure, however if sugar is added to water, then the pressure and hence the boiling point changes. The boiling point of a solution of sugar in water, or of a juice, under a given pressure, increases with the concentration of the solution. This is to say that decreasing purity also increases the boiling point.To explain in more detail, the increase in the boiling point of water depends on the number of molecules you add to the liquid. Sugar has very large molecules. Sugar has a molecular weight that is 3 times larger than that of salt. It does not split up in different particles when in water as salt does. So adding 7g of sugar into water you're adding 700,000,000,000,000,000,000 particles to the water. As soon as any of the sugar dissolves in the water, the boiling point of the water will begin to rise by half a degree Celsius for every 180 grams of sugar dissolved. Sugar in the water should raise the boiling point of the solution, meaning that it will need to reach a higher temperature before it begins to boil. Thus taking longer to boil, but raising the overall boiling point.