Question

why refill of a gel pen contain transparent liquid​

Answer 1

Answer:

Basically gel pen's ink is a suspension of colour particles in a water based gel,unlike the dye-alcohol thing in ballpoint pens. This thick and opaque gel-based ink can leak from the backside of the refill. So here comes the saviour-the stopper fluid. It's a thick gel that keeps the ink from leaking out.

Answer 2

Answer:

it consists of white liquid to maintain air pressure and prevent reverse flow of ink