  We consider a family of stochastic 2D Euler equations in vorticity form on
the torus, with transport type noises and $L^2$-initial data. Under a suitable
scaling of the noises, we show that the solutions converge weakly to that of
the deterministic 2D Navier--Stokes equations. Consequently, we deduce that the
weak solutions of the stochastic 2D Euler equations are approximately unique
and "weakly quenched exponential mixing".
