What compounds provides a slippery consistency in the lungs preventing alveoli walls from sticking together?

The slippery consistency in the lungs preventing alveoli walls from sticking together is provided by a substance called surfactant. Surfactant is a complex mixture of lipids and proteins that lines the alveoli and reduces the surface tension at the air-liquid interface. This prevents the alveoli from collapsing and allows for efficient gas exchange.