The time it takes to boil milk on a gas stove can vary depending on factors such as the amount of milk, the size and material of the pot, the heat setting, and the efficiency of the gas stove itself. Generally, it takes about 5 to 10 minutes to bring a small amount of milk to a boil on medium to medium-high heat.
However, it's essential to keep a close eye on the milk while heating it on the stove. Milk has a tendency to boil over or scorch if not monitored carefully. To prevent this, it's recommended to stir the milk frequently and reduce the heat to low as soon as it starts to boil.
Also, be cautious not to leave the stove unattended while boiling milk, as it can quickly boil over and create a mess or even pose a safety hazard. Always use a pot large enough to accommodate the milk without reaching the pot's brim when it boils.