Question

why does sugar dissolve very quickly is hot water comparing with cold water ​

Answer 1

hot water melts the tiny particles or crystals of sugar quickly as cold can not melt the crystals but dissolve it slowly..

Answer 2

The reason why sugar dissolves at a faster rate in hot water has to do with increased molecular motion. The added energy in the hot water causes water molecules to move faster and sucrose molecules to vibrate faster. This added movement tends to make the bonds between sucrose molecules easier to overcome.