How does the focal length,nature and refractive index of a convex and concave lens change when it is first placed in air and then a refracting liquid?

The focal length of both the lenses will increase when placed in a liquid having refractive index greater than the refractive index of that particular lens. (From the Lens maker formula)

 

The nature of the lenses changes when placed in a refracting liquid.

 

This can be explained by the following images for different cases.

 

 

 

Refractive index is the property of the material. Therefore the refractive index of both the lenses remain same.