For chemical experiments that involve gases as reactant and products, gas tube are used for their transport. Q1. Why are there differences in length of gas tube when in a round flask. In most case, entering tubes are longer than exiting tubes? Why is that? Q2. Why is sometimes the entering tubes submerged in the liquid (that is present in the flask) whereas sometimes they aren't? Q3. Are there any scenarios for which exiting tubes are submerged in the water/solvent?