A chemical dispensing apparatus to deliver a treatment solution includes a housing configured to be mounted to a wall surface and main fluid passage fitted with an inlet hose coupling at one end and an outlet hose coupling at an opposite end. A control valve is disposed across the main fluid passage at an upstream location and a flap valve is disposed across the main fluid passage at a downstream location of the control valve. A chemical mixing fluid passage is connected at one end to the first control valve and connected at an opposite end to the flap valve. A siphon tube connects a fluid accumulator and the chemical mixing fluid passage such that a flow of fluid through the chemical mixing passage results in liquid chemical contained in the fluid accumulator being drawn through the siphon tube into the flow of fluid through chemical mixing fluid passage.

A connecting structure for a liquid container includes a receiving groove. The liquid container having a suction tube is disposed in the receiving groove. A top end of the receiving groove is engaged with a connecting base. A front side of the connecting base is pivotally connected to a locking assembly protruding frontwards. A liftable base being movable along a top-bottom direction and a front-rear direction is disposed in an inner side of the connecting base, and has a bottom frame engaging with a sleeve that is for being connected to and communicating with a liquid pipeline and fits around the suction tube. Two extending arms extending frontwards out of the bottom frame are pivotally connected to the locking assembly. A left side and a right side of the bottom frame are pivotally connected to two swinging arms that extend backwards and are pivotally connected to the connecting base.