Question

why is there a chance of explosion when hydrogen chloride gas is led into water by a normal glass delivery tube

Answer 1

when HCl is led into the water, the reaction is highly exothermic. the amount of heat generated may exceed bearable magnitude of the glass hence may lead to explosion. This is basically due to high excitation of the electrons of HCl when added to water. Therefore while diluting the acids we prefer to add a few drops of acid slowly to the water and not water to the acid.